Step 1 . Drink beer
Wash with regular Dawn Dish washing soap to remove most of the oil and grime. Inside and out. Dry .
Depending on how many layers of paint and your desired finish.
For a rattle can quickie .
Step 2. Drink Beer
180,240 or 320 Grit DA paper use velcro backed papers if your sander has a velcro backing pad. Stickit paper works too.
Wear a dust mask.
Step 3 . Eat and drink beer
After sanding and before priming wash with Dawn or use a surface
cleaner / degreaser. Use multiple rags one to wipe more to dry as not to streak the surface.
Step 4.Burp and fart
Prime multiple coats . Depending on product and outside temps 15 to 20 minutes between coats ( same with color coats ). 3 good coats for coverage.
Step 5 Drink Beer
Sand with 400 to 600 wet or dry . By hand with a soft block or with your new toy.
If you burn through the primer, use a lite coat over those areas let dry then sand.
step 6. Stack empty cans
Before painting.
Wipe surface with degreaser , again one wet rag and more to dry.
If you're going to use a base /clear system. Again 15 to 20 minutes between coats (on the base coat). You can sand between coats if you want to, but why . Track parts.
If you're going to use a clear coat wait 45 minutes to 1 hour after the last base coat pass . Then clear.
Set 7.
Drink more beer and let dry.
Side note ....
Most autobody paint supply shops can pump base coats into rattle cans.
As posted above . Sprymax 2 part clear is really good .
WEAR a Respirator .