I'm going to show how I made a guitar that looks like Homer Simpson. It's not the best sounding or playing guitar, but that was not the point. I just wanted a hilarious looking guitar to hang on my wall. The neck is from a junk Hondo guitar that I got for free. I wanted it to have one single coil pickup so that it could fit entirely within his eye.
Step 1: Cut Out the Wood
This is just some 3/4" thick wood from Home Depot. I started with a large drawing of Homer. I cut out 2 pieces of wood in the shape of Homer's head. The wood pieces will be glued together later. Leave a little material around your drawing for trimming after gluing the pieces together.
For the piece that will be the top, cut out the neck pocket and pickup cavity. The extra hole below the pickup cavity is for the on/off switch. I used an on/off switch instead of a potentiometer for two reasons: 1. Normally I only use the volume knob on a guitar for turning it all the way down and 2. I was using a Strat tremolo bridge and the on/off switch fit nicely in the tremolo arm hole.
For the piece that will be the bottom, I routed where the wires will go. Notice that when the top piece is on the bottom piece the routed wire tunnel will intersect both the pickup cavity and the switch cavity. That wire tunnel also goes to where the jack will be.
Step 2: Laminating
Glue the 2 pieces together, clamp them and wait. Once dry use a band saw and/or belt sander to cut the sides down to the line you have drawn before. Then route the edges with a round-over router bit. I also drilled through the body because the strings will be strung though the rear of the guitar.
Step 3: Painting
Sand the guitar body and prime it. Once primed, mask off what will not be yellow. I used kitchen cabinet paper since it is sticky but won't leave any residue when it's removed. Spray that thing yellow. Remove the masking. Remask so only the beard is showing, spray the beard brown. Remove all masking and paint the black lines with a paint brush. Then finally clear coat the guitar. I used rattle can paint for everything.
Step 4: Finished!
Now assemble that beast and start-a-rocking!