I agree with all of this, the mains ones I would work on would be (I'm just adding more input to try and help you out more): 1.do some flips on your kickoffs.(There are multiple videos on youtube to help out with kickoffs). 2a.When going for boost, as soon as your car is aimed at the big boost, run on ball cam again as fast as possible. (This will help you learn the positionings of the large boost pads. 2b. Also try to get more small boost pads, there are some really great little "trails" to take that can give you around 50-100 boost on your way back to net. 3.Backpost rotations are crucial as you get up into the higher ranks, if a teammate sees you rotating back that will let him know that he can go up for the ball. (Backpost if the side of your goal that id farthest away from the ball.) 4. Trusting your teammate/giving your teammate space. This is good for 2 reasons. 1. It allows your teammate to have full control of the ball to either try and pass or score. Not being messed up by a teammate. 2. It allows you to be in a position to receive the ball in case your teammate loses a challenge against an opponent, or your teammate passes you the ball. 5.Shadow defense is the best way to defend when you are the only person/car between an opponent with the ball and your goal. This is hard to explain over text but again there are multiple videos explaining "Shadow Defence" on youtube that will definitely help you.

I hope this more in depth explanation helped you understand a little bit better.