I have found an easy way to make a quick dark eye look. I use a cotton pad for pattern. I cut it side in oval shape, then add it to my eye and start applying the shadows.
It's supper quick and looks really good. I always had problems painting my eyes symmetric. I have a witch mark on my eyelid and it always gets in a way making heavy make up :D And with cotton pads there is no need of drawing lines all you have to do is shade and add extra lines after it. You can experiment with it too...

So give a try and leave me a comment if it was useful. Or maybe you are already using such thing :)