The first few I did back in 2004-2005 sounded horrible. So I obtained a copy of Adobe Audition and sat down and learned it. It took forever. But if I knew what I was looking for in the first place it would been simple.
The trick is learning how to properly use a multi-track editor. Download a few montages that other users have posted, and copy the style. Do it until you get it right.
As for the material, go with what your mood is. If its upbeat, go with it.
If you can you must get Audition 2.0, they moved the features around, but it provides a higher quality sound for the final mix.