My nail polish cracks after I paint my nails?

Every time I paint my nails (in a french manicure) the polish cracks the next day. I let them dry and set, I have tried different clear coats, different white polish brands, I make sure my fingernails are clean before I paint them...I do everything! But for some reason, the day after I paint them they start to get cracks in the paint. And by the 4th or 5th day, they are completely cracked and it bugs me. What's the deal, and how can I fix/prevent it?