My foundation goes webby and cracked throughout the day?

First, use a makeup primer. Apply a tiny dime-sized amount of primer to your face and spread into a sheer, thin layer over your face. Then apply your foundation, making sure you don't use to much and blend very well. Then apply a small amount of powder. The primer will keep your foundation from smudging, bleeding off, look fresh, and keep it changing colors or cracking. Also, your problem might be because your skin is too dry or you're just using too much foundation. Try moisturizing your face and keeping the foundation amount to a minimal while blending well.