My simplest tips for live games, not sure if you've ever played at casino style event:
Keep the same mannerisms after each action. ie: after looking at your cards, always place them in the exact same position whether you have good or bad cards. If you think you are giving tells away after you have looked at your cards, don't look at them until it's your turn to play.
A very simple one, but if someone bets and you are going to call/raise, don't move your chips into position until it's your turn.
Ensure you are playing in turn. I've been guilty of playing out of turn and you feel like a real donk when the dealer reminds you.
Call out you raise. If the bet to you is $50 and you just put down a $500 chip, that's only a call - you have to announce a raise.
Pick a spot ont he table to concentrate on so that when you feel yourself getting a bit of nerves, you can stare at one spot and you aren't darting around the room with your eyes. Strike up some light conversation with your neighbor if neither one of you are in the hand. It gives you a bit of a breather and you don't have to keep up the tight persona while not playing which can help reduce anxiety.
Most importantly, watch other's mannerisms. I have WAY more success in live games than I do online because I find it really easy to judge the stregth of peoples hands based on jestures, movelemts and mannerisms.
You game knowledge is very strong and if you play tight in a $30 rebuy you will do fine. I know I wouldn't like my odds
of winning sitting at the same table as you.