Sand the branch lightly to remove any splinters or excess bark.
Hold the branch in one hand, and spray-paint the branch. Hold the spray can about 12 inches away from the branch. Move the can back and forth, and then up and down while you're spraying so an even coat of paint is applied. Use several light coats rather than one heavy coat. Let the branch dry for 24 hours or the amount of time specified on the can. If the branch is too heavy to hold while you're spraying it, place it on newspapers, and spray one side at a time.
Wrap the holiday lights around the branch. Start at the end of the lights nearest the plug. Wrap the lights from the bigger end of the branch to the narrow end.
Secure the light wires to the branch every 12 inches or so with a dab of hot glue. The closer you wrap the lights, the brighter the finished lighting fixture will be.
Find a branch that is reasonably straight with three equally spaced lower branches to provide a sturdy base so the upper part of the branch doesn't tip over.
Saw off the ends of the lower branches so the upper branch is level and the whole thing doesn't wobble.
Snip off any twigs that are in the way with clippers. Sand the branch, and stain it, if desired.
Remove the wiring from the old lamp, keeping the socket assembly together. You won't need the decorative lamp base -- just the guts.
Attach the lamp socket to the upper part of the wood. Drill two small holes that are the same distance apart as the two-hole strap fitting. Place the lamp socket assembly against the wood so it just peeks over the top of the wood. Screw in the screws to the two-hole strap fitting. It holds the socket in place.
Use a dab of hot glue to affix the cord to the back of the lamp until you reach the bottom of the base.
Place the lampshade onto the lamp socket. It should fit snugly around the socket. Screw in the light bulb.