Theres a bunch a youtube videos that go into great detail. A lot more than I'm willing to type right now. Go crazy, try different colors, the good thing about it is if you dont like it, some non-acetone fingernail polish remover and an old toothbrush will take it right off. Oh and clean towels, lots and lots of clean towels. I prefer paper towels just so they dont leave any fibers afterwards. But yeah, i saw an AR lower a guy did in red/white/blue with all the colors fading into each other. Looked pretty sweet, a bunch a glock guys are into it also. Just browse the ol interwebs and make sure you plan, plan for problems, and execute. Ya know measure twice, cut once motto... Good luck and post pics
BTW theres a method out there using crayons... Tisk tisk smh. It may work but show some pride in your firearms.