
I have been to a lot of canned shoots where the photographer has no idea what he wants, so the model has no idea what to do, so they wind of with a bunch of shots of her standing around trying to look pretty, but mostly looking bored.
So one thing I like to do is bring props to my shoots. It doesn't even matter what it is. If you can give a model something she can interact with, it breaks the tension, which means you're going to get natural expressions. Most models I've worked with really have fun with it, and any woman looks prettier when she's smiling.
If a model is tense, ask her to do something silly. I once had a lovely young model who was wearing an evening gown and was looking fabulous. Problem was, she was so anxious about shooting that she was clenched like a fist. I handed her a mop, and asked her to pretend she was fighting zombies. It gave her a laugh, loosened her up, and we got some great shots?
How do you put your models at ease? If you're a model, what could the photographer do to make your life easier?