Remove the strings, hardware, pickguard, knobs, and electronics
Mask any parts you do not want painted
Strip the old finish if needed
Sand the body smooth with progressively finer grits
Fill dents or chips with wood filler if necessary
Clean the surface thoroughly to remove dust and grease
Apply a primer suitable for the guitar body material
Sand the primer lightly after it dries
Apply thin, even coats of paint
Let each coat dry before applying the next
Build up multiple coats until coverage is even
Apply a clear coat for protection and shine
Let the finish cure fully
Wet sand and polish the clear coat if desired
Reassemble the guitar after the finish is fully cured