With some practice, you can definitely "carve out" a beautiful eye socket. You can also even out your face/eyes by strategically placing darker and lighter shades if necessary. It's all about placing the shades in the right spots.
Same goes for contouring your cheek bones, jawline, temples, nose, and hairline. For example, if you have a massive forehead, contouring your hairline will really do wonders in a very natural way
. It's also like an instant face lift (not that you need one, I'm just saying).
One method that is used in character make up can help you to learn contouring: If you want to practice, get a really dark color (much darker than your natural complexion) and practice on your face. You will see how these dark shadows will create dimension to your face and bring out "desirable" bone structure. Or, if placed in the wrong spots, will age you or highlight flaws in your bone structure. When you have an idea where to place the products, give it a go with "your" color. If it is well done, it is certainly subtle with no visible edges.
I hope that helps.