i Just put down the primary color i want for the guitar. I found that it still had some imperfection and can i sand them down and paint over them.
progressively sand it down and do another coat... assuming its the same colour, another full coat should do...

yes your supposed to do what deftonesordie said a couple of times, sand with 1200 grit and then again with 1500 and you should get a matte surface, sand away any shiny bits. and then laquer it when its perfectly matte, build up the laquer in lots of thin coats then sand again till matte and polish
yes, but the best results will be from wet sanding not dry sanding. start with @1200 grit and work up to @2000 grit. barely wet the surface, you don't want alot of water everywhere to possibly ruin the paint, just enought to lubricat it a little.
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