I was into detailing cars for many years, and there's nothing special about caring for a Tesla versus any other brand of car. Here's the drill:
-- thoroughly wash and dry the car.
-- use the clay on a small section at a time liberally spraying the area first with a lubricant. You want the clay to glide effortlessly versus sticking. The clay will grab and hold anything stuck to the paint and will show the dirt, so turn and fold often to expose fresh clay. Dry the area when done. When done, run the back of your hand across the surface and it will feel like glass.
-- inspect the paint. If there are small scratches or swirl marks, polish it, preferably with a random orbital buffer using a very small amount of product. As long as you are leaving a wet trail as you go back and forth, don't add more product as it is unnecessary and doing it this way leaves a very thin haze when dry, which you can then use a clean towel to remove.
-- wax the car, preferably with a random orbital buffer the same way as described above, for the exact same reasons.
I've used Griots products over the years. Good products, but pricey. I think products by 3M and Mothers are equally good. From my experience one product over another does not make as big a difference as the frequency with which you do the process outlined above. The thing that REALLY makes a difference is the random orbital buffer. Completely safe, won't harm the paint and makes the job go much, much quicker, principally because you use less product so there's less to clean off, and you let the machine do the work. And, a dual headed unit is even better as it allow you to get into smaller spaces. Here's the one I have used for 20+ years as it's extremely well built and very easy to handle:
Amazon.com: Cyclo Polisher: Automotive
You need to get different density foam pads for different uses, (ex: polishing is firmer than those for waxing) which attach to the heads by velcro.
Hope this helps.