They say beauty is in the eye of the beholder. The narrator offers that "Leah was tender eyed; but Rachel was beautiful and well favored" (29:17 KJV). It's not clear if this means Leah needs glasses and goes around squinting, or if her eyes are her only admirable feature (the NRSV translates the Hebrew word as "lovely" instead of "tender"). Either way, we're talking Pride and Prejudice here, where one sister's good looks make the other sisters pale in comparison.
Leah lucks out, though, because the deity in Genesis often sides with scorned women (think Hagar, 16:7-16; and Tamar, 38:1-30), and she wins the family record by giving birth to six sons and a daughter (30:20-21).