This is a great tutorial by Lisa Eldridge. I love it but I don't have a pencil like MAC's Chromagraphic pencil. So I did some thinking and came up with an alternative with what I had.
1) Right before you put on the concealer, dry your waterline. Take a q-tip or something similar and run it across the water line.
2) Chosse a concealer with good staying power and isn't too creamy, otherwise it travels to the corners of your eyes easily and builds up there.
Good-luck with this and I hope it helps!