OK, HELP! I have watched so many tutorials on layering, and either I'm really ignorant, or nobody has asked this before, because I can't find the answer to my question. When you layer in different colors and the bottom color is darker than the top, it shows through. How do I fix this? Is there a process that only cuts the part of each layer that you need in a certain color so that when you lay the next layer on top, it fits together like a puzzle