Just at home - some turn out good - some don't. Its just fun to do!
So what's wrong with the ones that don't turn out so good? focus? exposure? comp?
Honestly I take every picture that is worth anything through photoshop to at the very least adjust levels and a bit of sharpening. Not sure why but even when properly exposed shots from my D50 still need some levels adjustments. I wonder if some of your shots that you discard may actually be good shots w/ a little post processing. Of course the key is to nail it in camera and get it right but some things can be corrected after the fact if need be.
Oh and I shoot in RAW now and that allows me to adjust things like exposure, white balance, etc much more after the shot.