A good way to set up a compressor IS to start with fast attack, fast release, low threshold and high ratio - to really hear what's going on (and probably what you don't want). For me - I then get the attack slower until the right amount of the "front" of the sound is coming through. Then I back off the release until it bounces the way I want. Finally I reduce the ratio and back off the threshold until it works the way it's supposed too.....
Technical Editor, Sound On Sound