Pixel art is the obssession over details. If you draw a line and there's a stray dot, you erase that one dot. So really, what you need is patience (which I don't have) and skill (which I lack as well). I'm just as amazed as you are.
Now, for digital art that uses smooth strokes and such, like your avatar, I'd say you either need a mouse or a tablet. Mouse will drive you insane (well, me at least), but it is possible. Tablets are awesome: it's like drawing with a pencil, but it shows up on the screen. I half want one.