This technique works for just about anything--furniture, automobiles, guitars, etc.
For large projects (cars), power sanders and buffers are helpful. But for small things, it's great. And for beginners, hand-sanding and rubbing is less likely to burn or sand though paint and clear--it's a safer route...
Hey--it's a bit intimidating at first, but really not that difficult (with the right supplies.)
This example is a vintage thin-line hollow-body guitar that needed several structural repairs....
Step 1: Supplies
1) Rags. Lots of rags.
2) Wet/dry sandpaper-- 400 or 600 grit to start, 800, 1000, 2000 to finish.
3) A sponge for a sanding block.
4) A bucket of soapy water.
5) Rubbing compound.
Rubbing compounds and fine sandpaper can be found at automotive supply, home improvement, or craft stores.
Important Note: Avoid any rubbing or polishing compounds that contain silicon. It may look pretty, but any subsequent painting will be a nightmare!
6) Jewelers Rouge (or "polishing compound")
(ible user Spokehedz indicates that block polishing compounds like Jewelers Rouge are available at Home Depot. Any real hardware store is also a good source.)
Step 2: Getting started
And for smaller objects, a workspace is required. Even for cars, this should be done indoors.
I used a old workmate portable bench, and covered it with old towels. They help stabilize the work, and prevent scratching.
After this piece was repaired, it was sprayed with lacquer (five coats.) The resulting finish is a semi-gloss with a fair amount of pebbling and orange-peeling.
Lacquer should be allowed to dry for several weeks, but you can work with it sooner. Don't, under any circumstance, use any masking tape on fresh lacquer, even the blue "easy release" tape. You'll have to start all over...
These techniques aren't limited to lacquer, of course. Acrylic paints, urethanes, etc. will work just as well (and not have the long drying time of nitrocellulose lacquer.)