Tape off moldings
Get a water bottle with a squirter on it or a big sponge, add a little dish soap to the water
If you feel something on the piece of paper stop immediately, one piece of dirt or sand can wreck a lot of havok
Get a rubber squeegee (sp?) to clear the surface off to see the progress, a bondo spreader would also work
Be VERY careful on sanding edges and buffing them, don't buff in one spot too long or you'll burn the clear.
That's about all I could think of to add, if you have any more questions shoot me a IM, PM,... whatever or just post on here.