What makes faces look different?

While trying to model human faces I thought what parameters on our face make us look so different. The parameters are just eyes, mouth, eyebrow, nose, colour, etc. Just these some parametrs make a person look different! But how much difference in proportions will make a person morph into other? I think all parameters don’t affect the look equally.

What do u think?

When I try to draw faces, it always morph into another personality. I can’t figure out where I went wrong? Which parameters I must be most carefull of.

Please post ur thoughts here. If u know of any source on this then post the link here.