Its a very difficult question to answer as to explain it is to explain how to play poker well.
In a nutshell a strong player plays an acceptable V$IP/PFR/AF
he can be a LAG or a TAG, but he plays the opponent and the board rather than just the cards in his hand.
i.e. peeling flops for the sake of it is weak, but a strong player will do it against a weaker player if he feels there is a good chance he can resteal with ATC on the turn or river.
Strong players
bluff sometimes but generally do so against players they know will likely fold.
Usually when 2 strong players get into a big pot, they will both have very strong hands.
I know that dosent really explain it.. but its that type of thing.
How do you become a strong player.. that stoo big of a question and needs to be broken down nto lots of much samller questions, like, when do I bluff, when should I 3-bet / 4 bet, what type of boards hit this type of players range etc etc.