Ninjon, Miniac, Duncan Rhodes, Squidmar Miniatures, and Goobertown Hobbies on YouTube (or whichever frontend thereof) have some awesome tutorials. Be forewarned, you will get sucked in!
Not really, I just kind of wing it, honestly. I'd recommend printing in white or gray to begin with, but after that I just go for it. I figure if I completely screw it all up, I can just print another and start again, lol. I'm not an experienced painter by any means, but I enjoy it when I do. It's very relaxing to just throw on a podcast and zone out for a while.