Just a bit of practice. It's just like painting, only you're doing it on your face. Blend it in so it's smooth, and smudge it up over the top of the eyelid in a smooth, arcing motion, corner to corner. Not too high, you aren't going for the love child of a circus performer and a street girl.

[Thankfully Guttle has plenty of easily visible face, for demonstrating on. She does both his eyes, going slowly so every step can be clearly seen. It's easier to do this on something else, really.]