I'm a mediocre beginner racer, but hey, I'll give you my best critique. I also usually don't have anyone to train with, I like the video idea. I wonder if I could get someone who lives farther away but is a better racer than me to do something similar.
Anyway, your tacks look nice and smooth. On the upwind all I see is that I bet you could get a bit better angle by getting lower and more forward on the board.
Downwind, particularly on the first gybe, you come up pretty far before heading into the footswitch. I do the same thing so don't have any great ideas no how to minimize that. I think more sheeting in through the foot switch may help you to get away without heading up so much into it. I need to practice the same skill, though.
Your footwork on the gybes isn't as smooth as through the tacks. You might find the gybes go smoother if you can get a single foot motion forward and then back instead of stopping halfway on the board.
Honestly though you look faster than me so I'm not sure I'm the one to be giving you advice.