Blending eyeshadow on the lid can be tricky, so use a very neutral, pale shade of eye shadow (such as Pale Pebble or Almond) all over the lid. This provides a smooth, matte surface over which you can blend stronger shades.
The second trick, when correcting the shape of the eye, is to simply think about where natural light would hit the contour of the perfect eye, for example correcting:
Deep Set use a pale eye shadow or concealer on the whole eyelid. This creates the appearance of a very light, clean eyelid. Add to the definition by applying lots of mascara.
Drooping Lid using a mid to dark shade of eyeshadow draw a line of colour from the lash line to the browbone about a third of the way in from the outer corner of the eyelid. Use a soft brush to blend the colour along the browbone in towards the inner corner of the eyelid. Finish it off with a little pale eyeshadow at the outer corner of the eye to open it even more.
Protruding Lid when you look at the eye straight on you can see a lot of eyelid. Apply a soft grey/brown shade over the areas that the light hits on the lid to create an artificial shadow and then create a little light with a pale eyeshadow on the browbone to bring it forward.
Small Eyes applying eyeliner or eyeshadow all around the eye closes the eye and makes it look smaller. Pale eyeshadow or concealer between the outer lashes opens up small eyes, as does lots of mascara.
To draw the perfect socket line, look straight in the mirror and use a brush or sponge applicator behind the upper lid of an open eye to get the natural socket line.
When deciding which depth of shadow to use where, remember the basic rule: dark shadows deepen or hollow an area; light shadows make an area stand out. So light shadows look fresh on lids and browbones, darker shadows make the most of lashlines and contours.