One of the easiest ways to start drastically improving your poker winnings is to simply play more hands in position where you get to act last. More specifically this means playing more hands from seats like the button, the cutoff and the hijack.
The cutoff by the way is the seat directly to the right of the button and the hijack is two seats to the right of the button.
But you don't even have to take my word for it. You can go into whatever poker tracking program you use right now, such as PokerTracker, and see the results for yourself by sorting for winrate by position.