Didn't mean to dominate, but come one... what's easier than buying a can of duracoat that bonds incredibly well to the polymer Glock frame? Or you can just buy it done already from GB.com
It really is a great product. If you've ever done any spray-painting in your years and have the guts to detail strip your weapon down, then you've got pretty much the necessary skills to DIY. Just follow their directions and make sure to tape up anything you don't want the dura-coat to get into. Then hang up those pieces and go to town. (Don't let it drip and take your time with as many LIGHT coats as it takes)
Once you're done, if it's anywhere it shouldn't be, some fine sand paper will take care of it, and you're golden.