diamonds

Hey,

So i'm new, posting drawings in a couple of topics
and I have this one drawing, of marina & the diamonds.


I'm almost done with it but still not happy...
How do I get it to look more like her? (probably should've asked sooner)
Actually, more like, how do I get persons accurate on paper, not just her?
And how do you get clothes to look like clothes? Her sweater isn't done yet...
Thanks if you answer!
I appreciate it.