There was a good thread with a video of someone fixing rain spots on the front bumper of a Porsche. He wetsanded and then polished it all the way back with a rotary. I can't seem to find it and I really need to get back to work.
Anyway, it just showed how he always kept it moving, stepped up polishes gradually as needed, etc. I think it is really common sense, there's no black magic to it. I've only used a PC at this point, but I can really see how for major correction, it could really speed things up.