I've been an eyeliner fanatic since I was 12. Maybe it's because of my screwy witch eye, but I've always had a hard time getting both eyes to match. I finally learned a way to overcome this beauty handicap, and I think you might find it useful as well. Here is is: while applying your eyeliner, say to yourself (in your head, or you'll mess up), "I love you. I love you. I love you. I love you."
Like playing Astrojax, applying eyeliner can go wrong when I have negative thoughts swirling through my head. It's like my thoughts immediately influence my hand movements. When I focus on thinking "I love you," my body cooperates with my desires and we all get to feel pretty.