Please help my swim!

I have my 2nd tri (sprint) this Saturday and I have been reading on here about swim technique a little bit. I read something about thumbs entering the water first. Can someone elaborate on that point? Are you actually supposed to turn your palm outward prior to your hand entering the water? I've practiced that the last couple of times out and I just want to make sure I didn't read it wrong.

Also, how do you avoid getting kicked in the head without costing yourself too much time? I had planned to start on the outside of everyone but don't want to add 50m to my race.

Thanks!