Ah! the fun of polymer. http://www.nfobase.com/html/laura_liska.html
My friend Laura makes great polymer beads (well, used to...)and was known for her terrific use of color. She mixed her colors just using the color wheel and the three primary colors in Fimo. You may want check out this link i found on her, it might inspire you.
As far as texture goes, I have crumbled up Fimo and put it into a mini food processer and whirred it around for a few moments. The clay is still crumbly, but it is much easier to begin to kneed and soften. Really well conditioned clay gives better results. (maybe you can find a mini chopper second hand. Use it only for clay. But you knew that already)
After the clay comes out of the oven, you can sand the clay UNDER RUNNING WATER, with very fine grit wet/dry sandpaper, starting at 400 grit and working up to 1200. You can find it at the hardware store or automotive supply. The more patient you are, you can get quite a nice polish. Don't scrub the fimo with the sandpaper, just lightly sand under running water. If you have a Dremel tool you can buff your fimo with a muslin buff after you have sanded. I also know people who rub their beads and pendants on their jeans to shine them.
Some people even go so far as to wear latex gloves when working with the fimo...but that's no fun!