1. Be patient
2. See point 1
Seriously, patience is the best thing you can have in poker.
Also, understand variance happens. You can have aces and lose to a donk hand, but that happens, don't let it throw you off or put you on tilt. This kind of comes under point 1 as well, but losing a hand to a cooler or bad beat causes some people to make wild bets without good reason, trying to get their chips back, which can cause you to lose more chips as a result