You play only good starting hands.
If you have a strong starting hand you should make big open raises (min 4BB) or go all-in before the flop. Fold, if you have nothing.
I agree with most...however for me, it's staying patient for the long period of time.
I mean playing one free roll could take 3 or 4 hours for a chance to win $10.
Is is worth it?
Be very selective in the opening levels and very aggressive when you play. You may still get donked on but you get more value from strong hands off the weak players.