The basic rule about eye shapes is that is takes three shades to shape the eyes - a highlight, a mid and a defining shade. Using three shades will help you draw attention to the eyes, rather than the eye shadow.
Eye Shadow Three Shadow Application Tips
Mid Shade: Apply all over the lid from the lash line to the crease.
Defining Shade: Apply the darkest shade to the crease, blending out to the outer corner of the eye to contour and push areas back. You can also use this deeper shade close to the lash line for definition.
Highlight Shade: This is the lightest shade and it is applied sparingly under the brow bone and also to the inner eye near the tear duct giving a brighter, more open, brighter look. Placing a dab of highlighter in the centre of the eye lid will really make your eyes pop. Areas of the eye where we apply a light shade will visually come towards you and be emphasized.