Strategy. you are no doubt aware that you have different levels of punch & kicks. eg light, medium, hard.
the way it works is that the faster hits are light and the slow ones are hard.
its not just how much life you can remove by mashing the hard punches etc. the true way to beat your opponent is by hitting them first and knowing when not to hit them.
for example in an aerial fight (both players have jumped towards each other) if you tapped light punch and they hit a hard attack button, then you would connect first sending them to the ground.
combos are the next most important thing and the question is,"how can i further damage my opponent by chaining moves before they recover and are able to attack me again?"
the answer can be found by using the "training" option found in most capcom fighters or just buy in as player 2 on an snk game.
you will often find that a multitude of chained light punches and kicks is more valuable than one hard punch or kick.
my favourite little combo that can be done by pretty much any character is to jump toward the standing opponent, light punch them in the air on the way down, then when you land they are still recovering so light punch them again twice then crouch and give em a crouching light kick before leg sweeping to finish off with the opponent on the floor.
know when to use your supers as well. use training to learn how to get maximum damage and never ever ever execute a super combo when there is any less than 100% chance of success.
if the opponent blocks it then it leaves you open for them to execute a nonblockable attack back on you, or even worse they could avoid it and you could end up with your back to the opponent.
training mode.