Minimize curves and add definition with soft, angular styles. Higher temples will help create a longer look. Light colors and rimless styles help minimize the upper portion of the face. Choose frames no wider than the forehead, angling outward at the bottom corners. To reduce the angles use soft, curvy styles that give the face some definition.
Classic ovals are a good choice.
Soften the lower portion of the face by accentuating the eye area. Shapes with a straight top line or cat eyes with high temples work as long as the top is wide enough to balance the jawline. Frames can be top-heavy and angled inward at the bottom. Metal frames with rimless bottoms also are worth a try. Widen and shorten the face with styles that don't extend beyond the widest part of the face.