For jaws, we all know about V-lines. However, the slightly rounder version (oval shapes) is also very attractive. As far as chins go, the ideal length follows a 1:1:1 ratio (forehead to eyebrows = eyebrows to nose tip = nose tip to chin). But other than that, there’s not much to say. So long as the chin doesn’t recede, protrude, or isn't too wide or squareish that it disrupts the flow of the jawline.
♂ Guys: There is a little more leeway in men’s cheekbones and jawlines. Cheekbones of small-to-moderate size are well tolerated on men's faces, as they can be a manly trait. But beyond that, very wide cheekbones (ones that give “bumps” in the silhouette when looked at from front, like in the exaggerated cartoon below) are still seen as too strong and unfriendly.