Remove the wheels and trucks from your old skateboard using the screwdriver on the screw heads while twisting the nuts underneath the board with the socket wrench. Depending on your project's design, you may wish to also remove the grip tape on the deck. You can do this by aiming a hair dryer at the grip tape for a few minutes to soften the glue, and scraping the tape away with the razor blade.
Draw the shapes of the holes you plan to cut out with the marker on the skateboard deck. Tape the ends of the skateboard deck to two table surfaces to suspend the deck in place while you cut it.
Put on your safety glasses and work gloves. Use the rotary tool to cut holes of the desired shape and size into the skateboard deck, following the patterns you made with the marker.
Sand around the edges of the holes to remove sharp and jagged edges.