Tips for White Nail Designs
Use white polish that's good quality. You'll have to spend a bit more money on it, but it will last longer than cheap polish.
Use a white nail polish that is opaque and has no streaks in it. White nail polishes can be translucent, so if you're going for a light-colored effect, make sure your base coat is also white so that it won't show through your nail polish.
Do apply two coats of white polish and finish with a top coat. This will make sure your nails look smooth and shiny and will keep them from yellowing over time (which happens more quickly with white polish).
Don't use too much product! A little bit goes a long way with white nail polish, so try using just a small amount at first before adding more if needed.
Make sure all of the colors in your design complement each other well—if one or two don't match up well with each other, they'll look out of place against the rest of them.
Don't use too much glitter or shimmer in your white nail design. While it may look pretty at first, the excess pigment can make your nails look dirty after a few days of wear.
If you're going for a more textured look, try using different shades of white polish and adding texture with glitter or pearlescent powder.