Diversity is one of the keys to good looking scenery. I use over 20 different items plus stuff from the yard. As to how, a single book can't contain how to do it all, let alone a thread on a forum, but for begining I liked the books and videos by woodland scenics and the video from worlds greatest hobby with Micheal Gross. That and reading every magazine I can read, esp the old ones from the 60s-80s as they were more how to (IMHO). One trick that I have never read or heard that I discovered on my own is that when using ground cover/foam the base color of the "ground" can affect the color of the overlying flock/foam. You can paint one area forest green and another tan, apply flock, and end up with two different looking/color areas using the same cover. FRED