The orbital ridge is the area right beneath the browbone where it begins to slop into the crease. Sometimes, the orbital ridge and crease is used interchangeably like I have many times. But this time it won't because the orbital ridge does have some importance. It will create depth on the eye by creating a soft shadow for other eyeshadows. If you have a wide area between the lid and browbone and have often thought why eyeshadow doesn't look right, well this is the area to pay attention to. And, you aren't alone, many actors and actresses have the same eye structure but on tv/film the area is always colored without you knowing it.
The easiest and fastest brush to learn about coloring the orbital ridge and not to mention aiding in the separation of the eyes from the rest of the face which I covered in this post here, is the Cinema Secrets Crescent Shader #2 ($10). The pointed end dips into the crease and the flat end is dipped in shadow and is brushed onto the orbital ridge. See in the pictures below.
Does this brush work for all eye shapes? Pretty much, although the area colored may vary but it does act as a guide. You can use this brush all the time or once you learn, you can move onto other brushes.
Now, that you know about the orbital ridge, go try some tutorials on Into the Palette.