WARNING: ENORMOUS FILE.
This took me much longer than I originally anticipated. I have been working on this on and off for the last week. Since it's in beta, please be gentle. I'm submitting it off into the wild to see if any of the steps don't make sense, if anything needs visual clarification and, generally, to see if it's helpful.
This is my first tutorial. Since rendering and colour were the most popular answers to my "what should I make a tutorial on", I've made this.
If you like it, please share it with your friends. I hope it helps.