One big suggestion is to start with layers and create at least 3 levels of hair color: a dark base, a medium middle, and light highlights. Search the web for hair-care products for examples of the range of colors found in one person's hair and see where highlights should be applied. My last suggestion... use a less blocky brush. You have the right idea with multiple, thin strands, but it needs to... I donno... flow more, is the best I can describe it. Good luck!