Here's a short version of what was said in a mag which I should still have - somewhere. I haven't read it for quite a while so I hope this is accurate. I'm sure someone will be able to correct anything that isn't.
Try this on a drum track, preferably just a snare track. You set the compressor in a certain order and once you set one control, leave it and move on to the next without revisiting any changes you've made so far. The order is ATTACK, RELEASE, RATIO and finally THRESHOLD. Before you start set the compressor with the attack anywhere, ratio as fast as your compressor will let you, set the ratio as high as you can and threshold as low as you can. It will sound like crap with a horrible pumping sound but thats OK for this. What you've done is to seperate the attack from the rest of the snare sound so you can hear the changes you are about to make.
1: Attack: Adjusting this will affect the thickness of the hit. A shorter time will produce a thinner hit while a longer one will allow more of the signal in before compressing which will make it sound thicker.
2: Release: This affects the rhythm of the compression. Will every snare be compressed or every second one? The article was saying not to make it fast just because it might be a fast beat - the idea is to have as long a release as you can.
3: Ratio: This will control the size of the snare. A larger ratio will give more control over a sound (it will sit in the mix better) but at the cost of making it sound smaller. A smaller ratio will sound bigger but with less control.
4: Threshold: This controls at what point the compression will kick in. The article mentioned that you shouldn't have the compression constantly working but should kick in and out. The mag also said if you are after a certain effect, then these rules don't hold - do what you want.
I'm sure I've left something out but thats what I do remember.
