I could spend a boatload of time being more specific, but really the first half boils down to 2 thoughts:
* 3 Bet more pre-flop. "Fat, drunk and calling is no way to go through life son." -Dean Wermer.
* When you do open with a raise or 3-bet, after the flop CHOOSE A LINE that maximizes a chance to win the pot. (e.g. dont open a pot if you dont intend to fight for it.)
Sound simple, doesn't it?
and some words of wisdom I extracted from a podcast (talking about the flop decision to set up a line):
Look to bluff when you hand has very little show down value
Look to value bet when your hand is very strong
Look to check/call when you have a medium strength hand.