You have to know when to be aggressive and when not to be. This all depends on the table you are playing, tournament or cash or any discipline of poker. Since not all villains you face are the same, poker, as in life, is adaptation. To be a winner you have to adapt at all times in which level of the tournament you are in (beginning, intermediate, bubble, ITM, Final Table).
It's not that simple, there has to be a strategy to be successful in poker. Several experienced CardsChat colleagues have already said it; Important aspects: Discipline, Patience, Aggressive at the moment he touches, and knowing when to Fold and above all a lot of study of the rivals at the tables.