Here are a few pointers to improving your game while still having fun:
- Go into each game with the idea that you're going to do your best, but you are there to lose. Losing means learning, and it takes the pressure off. If you win, bonus.
- Pick ONE thing each game to work on. This could be your marine-splitting (slicing), your baneling-dropping, or your force field usage. No matter what, do that one thing at least a few times that game. If you improve, you can consider that a win.
- Work on one build at a time. Granted, you may have to pick a few different builds to suit different races your opponents play, but try to narrow it down to one per enemy race.
- Make sure you scout and macro, no matter what. I've lost SO many games due to lack of scouting or massively high minerals in the bank.