Try turning the model on an angle showing part of her hips and the rest of her curves but not all of them. Doing this will show she is a women with curves but lower the extreme or larger curves of the normal "crackhead" model figure
Get lower and shoot up with a wide angle, this will make the legs look longer as well as the rest of the body.
Finally if she has double chin problems shoot slightly downward for tight head shots, this slight angle is hard to notice when looking at the image yet hides some of the double chin underneath her facial structure and still looks natural.
Besides these posing tips, strong ratio lighting is always good (fade the heavier or larger sides out into darkness) you can never tell the true size of a women if you can not see all of her, yet done right gives a very romantic, sexy, fun feeling to the picture while keeping a professional quality to your image.