Here's a few tips...
1. Lay down a (scratch?) drum track first and record subsequent tracks while playing that back. Or use an external metronome, drum machine click track, etc. This ensures that all your files are recorded at the same speed.
2. With very little practice, you can use your software to visually locate and zoom in on the first part the sound and Select the portion of the wave before it. Then Cut that away and bam, you're cooking!. It's also is important to match the lengths of your Wavs when you are mixing multiple parts together.
3. I use a calculator to devide up the length of my ,say, initial 2 measure drum line (usually just kick and snare) into lenths of 1 beat, 2 beats, 1 measure, 4 measures, etc. and create a chart in a Wordpad document. Then when I want to add a new sound, I know at a glance exactly how long to make it.
4. If your working with final tracks, as opposed to creating from scratch, Cakewalk has methods of stretching or compressing track lengths to match eachother. Tip #1 will allow you to match up their start times.
Hope I helped some.
p.s. If you start getting weird clicks in your file as you mix wavs together, you'll need to find out how to Fade In/Out the ends of each seperate wav track (even the tiniest sample) and possibly how to D.C. Offset.
later