Watching more, some constructive criticism (and stuff I have been guilty of and still working on):
-One thing I would suggest, and I do this A LOT as well, is to maybe talk louder and emphasize pronunciation more. This is coming from a guy who deals with that everyday...I have a tiny speech problem in that I tend to "blur" my words together and it can sound like I am saying something completely different sometimes (it's even gotten me in trouble before).
There is nothing wrong with having a naturally quiet voice. I have the same type of voice. Make it work for you. The added pressure of being videotaped may skew what you're like, though.
-When writing on the board, my professors would get on my case hard if I was always "talking to the board." You're a righty? Put your right side toward the wall and write so that you can easily make little effort to turn to your left to speak to the class as you write. Especially since our voices are similar, the wall will absorb a lot of the sound and students may miss some important things you are saying.
-Try to let what you write be big enough.
it takes practice, though, because it's hard to visualize how the student sees the writing on the board to how you see it on the board.
Minor quips, though. You are doing great from my seat!