They make 4 sided blocks you can use to buff your nails before applying any polish. It helps the polish have more grooves to really grip the nail. Then, as others have said, you need a good base coat, 1-2 coats of color and good top coat. Don't go for the fast drying ones, just get a quality top coat. It also helps to do what they do at salons: swipe across the tip of all your nails to make sure the polish goes around the edge, not just up to it.