I'm in the FSD beta que and Tesla has given me a safety score. It's amazing the stuff you get away with and can still get a 98 or 99 score. I can accelerate as fast as I want - it doesn't penalize me at all. You can also speed, run red lights, and run stop signs. Ohh - you don' have to use turn signals, they could care less. Here's the big four that'll get your score knocked down:
Hard Braking - don't slam on your breaks to hard - they perceive this as a safety risk and dangerous driving (even if someone pulls out in front of you and you have to slam on your brakes) Best way around this is to super cautious of what's going on ahead of you. Leave plenty braking distance between you and the next car.
Unsafe following - This goes hand in hand with hard braking. If you, by nature love to tailgate you will have a terrible safety score. If you follow closely at high speeds, you get penalized more because your braking distance is less.
Aggressive turning - They penalize you on this one because it's a perceived danger to turn quickly (unsteady and unpredictable) I've had this one hurt my score by dodging a pothole or something and notice it later.
Auto lane/ auto brake corrections - self explanatory. If you are running off the road or about to hit another car and the car has to step in.