1) Train hard but remember to train smart!
2) When you are competing make sure you go into your matches with an open mind and remember that anything can happen!
3) Make sure you are composed and not letting emotions cloud your judgement in preparation or competition.
4) In your match, when you see something go for it! Never second guess yourself or your skills.
5) Most importantly is to have fun! It's a competitive tournament and winning is the goal but if you remember to have fun you will never truly lose and only learn valuable lessons for the next time.
The first time I ever competed was in 2007 in Las Vegas at a Mr. Olympia grappling tournament, only 8 months after I started training MMA!