Cheese grater to rough contour, then foamglass (fartblock), then either the long or short curved hand blocks to prep for primer, spray the primer, then dust with rattlecan, then use block again, wetsanding with light touch to find high and low spots. Fix those high and low spots with elbow grease, NOT pressing hard but repetition.
If you're asking about the sander to remove paint, skipit. Aircraft stripper and a scraper, then DA clean up using appropriate grit depending on whether you are on metal or trying to remove some yahoo's crappy bondo work.
Use hammer and dolly to get the sheetmetal back as close as possible to contours if you aren't replacing panels. Keep in mind how much your time is worth and consider replacing with new sheetmetal (or fiberglass) like from AMD or AAR fiberglass. Patch the damn rust, don't bondo or glass over it.
I hope that helps.
Oh, I forgot to mention. Don't work the metal too much if you can help it, you run the risk of getting it thin and hard from working it.
