I'm new at knife making and sharpening, so I'm still a little scared to do much sharpening on a belt. This is the method I use, and I believe it's good for beginners because you don't risk taking too much metal off of the knife with the belt grinder.
Once I'm ready to sharpen the knife, I first grind my initial edge with a 220 grit belt. It usually takes me anywhere from two to four passes per blade side. I then use the finest file I have and make passes on each side of the blade until I get my wire edge. The file will feel like it's skating off the blade, but it is taking a little metal with it. Once the knive feels sharp I take it to the leather strap to finish it off. You should be able to shave hair now.
I hope this helps. -chris