Relax. Don't do it. ;)

She needs to like her body (or parts of it) & she must not feel pressurized
 

In my limited experience ...

If she feels pressured to do anything there will probably be a bad reaction.

Most women are unnecessarily embarrassed about parts, or all, of their bodies. They compare themselves with Photoshopped models who, even in their natural state, are selected (slim non-buxom figures, unlike most of the history of erotic art), dressed, coiffed and photographed by, what I imagine, are a disproportionately high number of gay men in the fashion industry. If that is so, many women are trying to make themselves sexually attractive to gay men!

She does not have to feel like a world class model, just feel desired by you (assuming you are not swingers).

The few women I have spoken to about this, are ashamed about things like eg "my bum's too big" - when I suggest that their partner might appreciate that part of their body, they often smile.

You probably also show how much you like her body ("mmm I like the way this curves") - especially the bits she is embarrassed/ashamed of.

Suggestion: during sex, ask her to show you how she likes being touched. This can turn into a little solo show, which can build her confidence in showing herself and become something she can do outside of the bedroom.

Women who like their bodies and feel body confident tend to want more sex. It is said that women need to feel happy first in order to want sex, but men want sex in order to be happy.

You could start by asking her to show off (clothed or not) just the part of her body she seems to like - then ask to photograph just that area.

If you, later on, ever go to a naturist beach/club/resort she will see many women "worse" looking than her and become more relaxed about being naked.

/end of lecture, stating the obvious.

Compliments
 

Let her know when a person she might think is attractive has taken a second look at her. Be specific; legs, butt face or chest. Go slow