One thing that I have always believed to be important is to compliment a model on what she is *doing* - on her posing, her effort, her skill - not on her appearance - or more specifically, her body - in order to avoid any sense of impropriety
I was apparently wrong....
I have worked with models who have complained about a body part or their shape or whatnot, usually while naked -
after a while I have felt like I had to say *something*.....
So I usually say that I do now know her well enough yet to compliment her (fill in body part, body, whatever she is complaining about)
more often than not, they follow up with something like
"when will you know me well enough"
"sure you do"
or along those lines -
so I convey my opinion, and it seems to make people happy.....