Representing likeness in illustration?

Hi r/illustration

I really struggle with representing likeness in my illustrations. I'm currently design a series of minimal cartoon/emoji versions of public figures & Celebrities and they turn out well but they just look like a person not the recognisable people they are.

Apart from hairstyles, clothing and other facial features I've got what else can I do to make it look like the person I'm trying to create?

Any tips or suggestions?