First of all hi man.Answering your question :
1- foward facial's bones growth.Otherwise you will have resessed bones = unnatractive
2-eye sockets,very important.Eye sockets along a proper eyebrow's trim give you plus point
3-cheekbones.very important to max your looks.More rounded cheekbones mean more prominent = more handsome
4-jawline,or like many call it,chiseled jawline = indicator of low body fat PLUS square face and even the muscles of the jaw called masseter muscle,are more ripped = handsome.
You see,when you are that good looking with a nice structure,lips sizes can't be too important.You could have small,medium or big lips,and you will still look good thanks to the facial overall structure.Many people with ripped faces known in the mgtow comunnity as chads or tyrones (black chads of course) claims that some stupid exercises can rip your jawline and help you achieving it.They recommend the MEWING which consist in make all days an specific amount of bites to exercise the muscles of jaw.In reality,all this is dangerous why? because in long term it will damage the muscles and the nerves.So,NO,mewing won't help you out with getting a jawline.Lowing your bodyfat will help and your genes of course.Hope that helps.