Step 1: Supplies
1) Food Coloring (the kind that comes out in drops is easiest to use)
2) Tooth Picks (Bamboo sticks for shish kabobs also work really well)
3) White Nail Polish (light colors also work)
Step 2: Adding Colors
Add the food coloring directly to the bottle of nail polish. Sometimes it can pool up at the top and not sink. If it does this you can stick a tooth pick in, and it will help move the food coloring around.