Pull hair back and compare face length to width. If the face is significantly longer than wide and the sides run roughly straight from forehead to jaw without much tapering or widening, you have an oblong face.
Adding width and shortening the perceived face length are the priorities. Volume at the sides, minimal height at the crown.
Wide, tall frames add horizontal visual weight and reduce the perception of face length. Avoid narrow frames that emphasize vertical lines.
Wide frames are essential. The wider the frame, the more it counteracts face length.