A couple of things help. One is time- in general, the longer the beer sits, the clearer it is. So, patience often helps. Another thing that helps is careful racking- leaving all the trub behind when racking to the bottling bucket. One common cause of cloudy beer is chill haze- that's when protein particles are obvious when the beer is cold. This can be prevented by getting a good "cold break" when chilling the wort, as well as using kettle finings like whirlfloc in the boil. The key to a good cold break is getting the wort from boiling to under 70 degrees in under 20 minutes or so. Then, great big globs of coagulated protein fall out of the beer. I'll see if I can find a picture- it's good for the beer, but looks really gross! Also, a good strong boil and a good "hot break" hellp.