My first guitar, i had it for a year and then decided that it needed a overhaul.
so i sanded it down to the wood ,then
i decided a design i wanted on it drew it out on some scratch paper,
and then i drew it on the guitar, ( you can make a stencil for it as well),
i find it easier to just free hand draw it on the guitar its self.
once you have it on the guitar use a wood burner and trace over the design so that it burns into the guitar, (push down into the wood with the burner as you trace the design, you can decide on the depth by how much pressure you use )
after you have it burnt inti the guitar decide on the color of paint or stain you want to use i used both stain and paint (enamel paint works the best , STAY AWAY FROM LAYTEX PAINT IT WILL PEEL OFF AND CRACK  and it really don't look that great lol) , but its your choice on what you decide to use after you get the guitar painted and/or stained use a thick lacquer or polyurethane to seal it you may want to use at least 3 coats of polyurethane so you can have a good protective coat on the guitar after the first coat of polyurethane (once its dry) use steel wool before the second and third coats iby doing the steal wool you can make the polyurethane look like a coat of glass it will be so clear and shiny . then put your electronic parts back on the guitar  and jam away.