Do research: Start at the Tesla Motors website, to there look at the features. Click into the Updates area and there browse the Blogs, the Videos, and the Customer Stories. Search the Web for recent entries about the car and see what owners have to say about their vehicle. Go into YouTube for recent videos about the car, to get a sense of what it's like. In states which have a Tesla showroom (Massachusetts has two), go see the car in person. Sit in it and really experience it. Open the frunk and see the space you've been deprived of all these years in owning an internal combustion engine car. Go into the trunk and see how spacious it is, rather like a station wagon, and don't miss the deep well back there which gives you even more space.
Evaluate the dimensions and weight of the car relative to the space you have for parking. Think about charging the car: you will probably want to install a 220V, 50A outlet near the rear of the prospective car; and if your breaker box is not at least 200 Amp, consider an upgrade.
Go for a test drive. A Tesla Motors showroom will be happy to schedule a test drive for you. Have your driver's license with you, of course. At the Massachusetts Natick Mall showroom, you would tell them the version of Model S that you are interested in, plus options, and they will use the closest demo car they have. The cars for that showroom are parked in the parking garage behind J.C. Penney. Their test drive consists of getting you familiar with operation of the car, after which you get onto the Mass. Pike to drive one exit westbound, and then return on Route 9. After the test drive you can return to the showroom with the rep and order a car, if you choose. This is a good way to do it, rather than online, as you will have an interested and informative person next to you in the process, who can answer your questions.
Note that there is no price negotiation: there is no game-playing, as most of us have been highly annoyed to find at conventional car dealerships (even the most reputable ones). There are no trick fees, no "Let me confer with my manager" price nonsense, no "undercoating" or other devious incitements, no hassles.
Note that the car comes with a built-in alarm. In the past, Lojack would be added to cars (for a considerable fee) to provide a theft-deterring alarm and aid in finding the stolen car. Lojack is largely obsolete these days, particularly as cars such as the Tesla have GPS location findability. (Tesla Motors headquarters can assist in tracking a stolen Model S, if needed.) Be aware that, perhaps counterintuitively, the more expensive the car, the less appeal there is for stealing it for parts. This is because owners of more expensive cars insist on primary-source parts, and so there is no market for dubious-source parts.
The Tesla website's Order section used to include "Finance" in addition to Cash and Lease price number, but no longer has that. However, when I went to buy the car, Tesla financing was available — and at a very attractive rate. This made for one-stop shopping, making the buying process much easier. They provided a rate quote within hours, with quick approval.
I contacted my company (Liberty Mutual) by email to solicit a sense of cost, talking up the safety features, the Model S being the best car that Consumer Reports had ever tested, and other awards. I got a call from the local office agent, who said that they knew little about the car, which she pronounced "Telsa". When I asked about the elevated cost, given all the safety features this car had relative to my current car, she could only say "that's just the way it is". What a substandard response. I wrote to their president's office to try to bring their standards up. When I mentioned this to the Tesla rep, he said that this level of ignorance is common among insurance companies.
Insurance for a high-value car like the Model S is going to cost more simply because the car is worth more, which has to be covered in case an uninsured motorist collides with your car, etc. But, do shop around, and evaluate the coverage points in your policy. Also, look for discount programs, as possibly provided by your employer, or through an organization like AARP. I finally got connected with a clueful agent and, with a program discount, got a reasonable policy quote.
You now have seven days from the time of ordering to make any changes in your order, or cancel the order without penalty. Changes to options/choices can be made in the My Tesla site. At the conclusion of the first week, your order enters the production process. You can monitor status on the My Tesla page. Oddly, they don't seem to notify you when building of the car is completed: only by continually inspecting the My Tesla site do you learn this. Now the car has to be shipped across the country, to your Tesla Service Center.
You should now be getting email from your local Tesla Service Center customer rep — whom you may not realize is local versus central for lack of such identification in the emails. The amount of time from ordering the car to availability of pickup varies: my time was just under a month. Now is the time to request that this Tesla representative get an electric vehicle registration plate for your new Model S, if your state provides them. (Massachusetts does: EV plates) At a minimum, this is what first-responders first look for to realize that they are dealing with an electric car, to know where and where not to cut, etc.
About trade-ins: Yes, Tesla accepts trade-ins. Like any dealer, you will get about half what the dealer will sell it for in a retail space, because they would need to recondition the car for sale to a retail buyer. If, instead, they are just going to sell it at auction, they won't get as much as retail, and again the amount you will get reflects that. You could sell the car yourself — but there are few things more risky or hassle-ridden as self-selling a car: if there is anything found wrong with it, even if it happenstance occurred any time after the sale, the buyer is going to come down on you. If there is any kind of accident, they are likely to come after you, claiming a maintenance issue. It is far, far safer, and probably cheaper in the long run, to simply trade the car in to the dealer and have no worries. So, with Tesla, how does this work? Tesla will inform you that an independent evaluation company will be contacting you to inspect the car. That company contacts you, and arranges a time when they can inspect the car — which can be anywhere (at your home, your place of work). They sit in the driver's seat, record numbers, look it over, open the hood, check the oil level, open the trunk and rummage around in there, etc. They do not drive the car. At the conclusion they say goodbye. Some time later Tesla will contact you with an offer based upon that evaluation. If you accept, that number will be folded into the sales agreement, deducted from the balance due.
Taking ownership of the new Model S: This will occur at the local Tesla Service Center. (There are some YouTube videos showing home delivery, but that was largely an exceptional early program, when Service Centers had not been established.) You clean out your old car, except for its owner's manual, and anything else that should stay with the car. (Remember to remove any toll road transponder.) You bring with you the registration paper (which you keep), the title document for your old car, plus all its keys. You also bring a check for the amount shown due on the sales agreement. My Tesla rep said that if the amount due is around $40,000 or less that a personal check will be fine: if higher, a cashier's check is required. You sign various papers, including the loan agreement. The rep then takes you to the car. Yowza! You should now inspect it for having everything that you ordered. You now sit in the driver's seat. The rep will sit beside you, explaining all the features of the car. Someone will remove the plates from your old car and give them to you. (Massachusetts doesn't want the old plates back: you simply fill out an online form, where at the end of the process they tell you to fold the plates in half and recycle them.) Finally, you drive home with your new Model S.
A word on the take-ownership process at the Service Center: YouTube videos show the buyer taking ownership in a gleaming building interior, in a very appealing process. My process occurred at the Watertown, MA Service Center. That is the most cramped facility you could imaging, where it was almost impossible for me to fit my old car into the lot there. The Model S transfer process occurred outside, behind the building, as employees barely squeezed other vehicles past my Model S. This was more like a "Joe's Garage" environment than a high-end car facility. The staff there is obviously stressed, trying to deal with a bad situation. And the car was only half-charged: they had it plugged in during the transfer, where this was obviously a rushed process. As I've written to Tesla, they very much need to move out of that horrible bulding into something more appropriate, and in an area that is closer to where their buyers characteristically live. Tesla has since opened their Dedham, MA facility, which is much more spacious; but the Watertown facility still remains.
If you had an E-ZPass transponder inside your old car, be aware that it is unlikely to work in the Tesla. A growing number of cars are such that the transponder won't work through the glass. When I went through the E-ZPass toll lane, instead of the green Thank You light I got a yellow Call E-ZPass light. I called them, was informed of the issue, where they recommended that I swap my internal transponder for an external one, which I did. That mounts to the top of the front plate. But there's a problem: The front of the Tesla nosecone is curved, with the plate mounted curved to it, while the external transponder is rigidly flat. I solved this via a strip of neoprene rubber compressed between the plate and transponder, filling the void between flat and curved, without absorbing water. (An old mousepad served as my source of neoprene.)
Remember to sign up for the Service Program, which you can do on the My Tesla site.
Consider ordering a Mobile Connector Bundle from the Tesla online store. This will allow you to keep the charging cable packet that came with the car in your car for on-the-go charging, and leave this newly purchased bundle connected in your garage. You may be surprised to realize that the MCB does not come with an SAE J1772 public charging station adapter, as you got with the car: this is apparently because people purchase the MCB for the garage, where such an adapter is of no value.
Order the center console insert (Premium Front Console) if you want cabin stowage space. Be aware that their production has been very limited such that there is a long wait for them. You can instead by a center console insert (CCI) from a third party such as Evannex — but I find these 3rd party units to be relatively amateurish and unsatisfactory, obsessed with cupholders.
Remember to order snow tires (from the Tesla online store) as winter draws near.
An important thing: Learn how to wash your car! You just invested a lot of money in a high-end car. You just got it. This, now, is your one opportunity to avoid doing damage to that glowing finish, while it's still perfect. Uninformed cleaning methods are the way you irrevocably ruin the finish on your car. There are excellent videos on YouTube about what to do, and what not to do. Do not put an expensive car through a car wash: it's simply too punishing. Do not wash your car in direct sunlight or when temperatures are hot: the water will too quickly evaporate and leave spots; and spraying cold water on a hot finish is going to stress it. Buy a high quality car washing liquid, and follow its instructions. Buy either a shag-type washing mit or a microfiber cloth or a natural sponge (where you use the natural side on the car finish, not the factory cut side). Do not use household sponges, which are too firm and will hold dirt and then press its sharp edges into the paint. Rinse the car thoroughly, but don't power-spray it: your goal is to allow dirt to lift off the surface and float away, not bombard the finish. Use a clean bucket and generate a soapy, bubbly mix in it. Dunk your washing mit/sponge in it. Without excessive force, swirl that over a wet section of the car. Do not try to clean more than a roughly 4x4' section of the car at one time, to avoid having the surface behind you dry. Rinse that just-washed section clean, with moderate water pressure: this gets the dirt off the car, while it is in suspension. Do not immediately dunk the mit back into that soap bucket: rinse it either in a separate bucket of plain water, or play the hose over it. After the car is fully washed, you should dry it. Eh? You've never before dried your car after washing it? Water droplets on the car will absorb atmospheric dust, starting immediately after you've washed that area. If you simply let that air-dry, you will have a car covered with ugly spots, and that defeats the purpose of the exercise. To get residual water off the car, microfiber cloths are the recommended method, where you should use a medium pile weight cloth. (A natural inclination is to use the plushest pile you can buy; but that's counterproductive in that the pile is too tall and bends over, where a microfiber cloth is only effective where the ends of its fibers touch the surface.) Do not use an ordinary towel: those are notorious lint shedders. Never use one of those silicone squegees: those are a "what were they thinking?" types of device, which will scrape dirt particles against your finish. You would also think that a dry microfiber cloth would be best to use; but the cloth works better when it is somewhat wet such that the water molecules are better pulled into the cloth. This gets us to the very best approach to drying a car... Rather than just wipe it dry, let the properties of water help you dry it. A sprayed car will be covered with a huge number of individual small droplets. Water exhibits surface tension, where it very much wants to bond with other water molecules (hence the tightly cohesive water droplets). You can get almost all the residual water off you car with little effort and no contact by doing as follows: Remove the sprayer from the end of your hose such that the end is fully open to water coming out at minimal pressure. Now turn on the water and hold the end of the hose over the car. Flood the surface with water and slowly progress over all of the car. What happens is that the water sheet will be cohesive, wanting to pull every molecule of water with it. The result will be a surface which is amazingly all but water-free. You can use a microfiber cloth to blot away any that remains.