Before playing you need to analyze your cards, your position at the table, how many opponents acted before you, how many are yet to act, when your stack, pot value, tournament stage, opponents' style, tournament structure, speed of buyins, your image on the table, your opponents image, and on top of that all create a suitable hand range ...
We will usually play most of the time on automatic without analyzing all these details, but it is still important to try to play consistently, to avoid letting opponents read your game, not to give free cards, and not to risk too much and involve all chips in tricky plays.
A good strategy is to always be aggressive, prefer to play in late positions, if you are in early positions be aggressive but be careful when analyzing the board, and do not underestimate your opponent, in early positions it may be more profitable to avoid getting involved in hands that don't have a ready hand and have readings from the opponent that indicate danger.