I find that this is a great tip to use when creating an eye look perfect for a night out so I thought I'd share it with you :D
You can follow these instructions using the picture below :)
Step 1: Get a credit card, train ticket, ruler (pretty much anything with a straight edge) and align it so that it joins your outer corner of your eye to the end of your eyebrow (you can adjust it depending on what you want your wing to look like, but this is a pretty good way of getting it just right)
Step 2: Smudge your eyeshadow all over your eye and outwards towards the card, I'm using Rimmel Colour Mousse Eyeshadow in Galaxy
Step 3: Remove the card, et voila, a perfect eyeshadow wing!