I LOVE nail art! You could use red, black, and white for a Minnie or Mickey Mouse design with scotch tape. If I wanted to do a Minnie design, I'd paint all my nails red and use the tape to make a bow design of my ring finger. The bow design can be made by folding a long piece of tape (unevenly so you can open it again) and cut one side of the bow into the fold so when you unfold it, there's a symmetrical bow. I used to do the same thing with paper to cut out hearts on Valentine's Day. Then you put the shape on your nail and paint over it with black nail polish to have a black bow.
Sorry if that was lengthy, lol. Try looking at YouTube for tutorials also.