usually for local models...
1) wear a thickly padded bra (no offence)
2) stop wearing colored contacts because they're not natural. the eyes look glassy and dead with them on.
erm... i'm not a portrait shooter but.. i did notice that if you ask the model to push her chest together with her arms..to "increase" the size overall... i did see an increase in comments and compliments.
good luck!
If beauty is defined in the chest then we really need to examine ourselves to see what our definition of beauty is actually. But as you say, this is applied in a local context, so I guess people here in CS P&P do have such inclinations based on the numerous comments I've seen.
Anyways, for flattery, it's no different from landscapes, you hide what you want to hide, and you show what you want to show.
If your model has a upturned nose, you take the trouble to avoid up-nose poses, or a low angle which will emphasize such a flaw.
If your model has a short body, you could instruct her to wear clothes that hide that fact.
If your model has long legs, you can emphasize this with focal length choice (though please, not overdone like I've seen here before)
I could write a lot more (and I admit, I haven't shot any model, ever, though why does that matter, I wonder?); but the bottomline is, understand your equipment - what each of your lenses can do, understand perspective, understand what your objectives are when capturing shots, understand the light and you will not go wrong.
Most importantly, you can't squeeze water from a stone. So if a 90 kg model at a height of 1.5 metres asks to look like Kate Beckinsale (in a full length shot, at that; it's possible to be done via a close-up if she isn't hideous), I guess you just have to put your foot down and tell her to look in the mirror.