The only things I have to add:
1. Go in with realistic expectations. Your $300 could last you 2 days or 2 hours. Play the best you can, have FUN, be prepared to accept any result.
2. Consider shortstacking if you play NL - here's an old post of mine where I talk about it:
https://forumserver.twoplustwo.com/3...05/?highlight=
3. Consider looking for a fixed-limit game. You won't WIN as much playing fixed limit, but your money will most likely last longer. Buy the book "Small Stakes Hold'Em" by Miller, Sklansky and Malmuth to learn how to play.
Don't forget that most Vegas casinos have free drinks while you're playing!
Have fun
DTXCF