Tilting forward may help, if you can use those types of poses.
Also, if you can use angle light, or angled behind lights, the shadows will accentuate the chest. However, getting this right may be tricky, because the face may need different lighting, or will show bad face texture or shadows. So you will have to have her turn the head to a different direction where it is also being lit well.
Also, Photoshop, e.g. Liquify helps. :-)