Few rules that some people dont know.

For instance someone bets and you want to re-raise say "raise" then you may string bet.

String bet is taking chips from your stack and placing them into the pot then going back to you chip stack to get more. Imo thats a no no. Some ppl let it some dont. If you dont have to show your hand then dont.

If you say "fold", "raise", "call", or "all-in" then you must respect what you said and back it up. Thats a few rules that I know of but every tourney is different.