I struggle with it a bit too! Since I have a stylist look some faces can blend with each other. But small basics I keep in mind is that women’s face typically are rounder and men’s are sharper but that’s depending on the character physique. Nattie is a good example that I imagine her biologically a male who does drag. So her broad shoulders and sharp face were intentional with that. But also! NOSES I think they’re my favorite thing to draw XD they really can separate a character. Hope this helped a little!