You'll begin by priming your eye to receive (and hold) the makeup you'll be applying. This will hold the shadow in place as well as provide an evening base that will help smooth everything out.
You can use eye shadow primer for this step, which is a nude, liquidy, foundationlike makeup. If you don't have primer, you can also use undereye concealer or the same foundation you use all over your face.
Spread a thin, even layer over your entire lid, from lash line to brow. Don't forget to use your undereye concealer under your eyes at this point, too, if that's part of your routine.
With your eyes primed, you'll be reaching for your eyeliner.