Keep in mind the difference between directional and punch buttons.

Your punches count only if you hit your opponent in the head. Don't bother giving body blows.

Picking a corner at the beginning of the game is more of a which corner are you used to than anything else.

Lure the opponent a bit by moving away from him and attack as soon as he approaches.

When you get knocked down tap as fast as you can to get him up.