An additional comment:
Your preflop standards should, optimally, be roughly proportional to your skill. The better you can play postflop (that is, the fewer mistakes you make) the more hands you can profitably play preflop. The problem with this statement is that I don't know of any poker player that doesn't severely overestimate his own skill (myself included, of course) which means that we all have a tendency to play too many hands.
If you're new to shorthanded play, tighten up. Perhaps play just as tight (or even tighter!) than you would at a full table, until you figure out what's going on. The tighter you play, the easier your postflop decisions will be which translates directly to you making fewer mistakes. When you're working your way up to being a winning player, one of the key points to focus on is avoiding situations where you have to make difficult decisions.
As a sidenote, once you're a winning player and want to become better, that's when you may actually consider purposefully placing yourself in difficult situations just to learn from them. The reason I started playing 6-max was actually for that reason; to challenge myself with more tricky situations. That I ended up falling in love with it and staying (for glory and, to no small extent, profit) is just the ending of a happy story.