The great thing about collage is that there really are no rules... you're only limited by your imagination.
If you want to learn how to draw, an EXCELLENT book is "Drawing on the Right Side of the Brain" by Betty Edwards. Truly excellent, really.
As for learning how to knit... it's hard to say if you'll be able to teach yourself or not. I'm *mostly* self-taught - a friend taught me how to cast on, and I figured out the rest on my own. A good place to start to get an idea of how involved it is would be http://www.lionbrand.com - on the top of the page, click the "learn to knit" link. There's a series of tutorials that teach you everything you need to know, with really clear illustrations.