1, two coating
Dark Nail Polish too thickly coated easily fall off, in order to avoid this situation, two paint thin all the time, and in the middle to allow sufficient time for the first layer dry completely.
2, quality of Nail Polish
Quality of each kind of nail polish is different, if you do that, but didn't get the effect you want, consider a different brand of nail polish.
3, grinding and polishing nails
If the nail is not flat, then don't expect coloured nail polish can hide it. Nails reflect the person's State of health, so if your nails appear on inequalities stripes may be physical reasons.
4, James bottoms
Before you apply dark Nail Polish must be coated with a layer of oil, while protecting the fingernails can make nails more smooth surface, but also to prevent bleaching.