First, take a look at your eyes in the mirror. Do they look close together or far apart? If you have wide spaced eyes, you want to put the DARKER shade of color in the inside corner of the eyelid. If you have more close space eyes you want to put your LIGHTER shade of color in the inside corner.
It's a term we use in the business called "highlighting and contouring". It helps give the illusion that you want to create.
After you apply your darker/lighter shade of color then use the opposite color on the rest of the eye. You can line your lash line with a dark shadow or eye pencil to pop the eye more and that's it. Apply mascara always and Voila!
Keeping it simple will always create a beautiful, clean eye.