My tips are based on my experience as a petite model in NYC:
1. Diversity: Don't just shoot in thongs. Shoot in full back underwear, boyshorts, and panties of all kinds.
2. Posing: Lingerie modeling isn't just about showing it and flaunting it, sometimes it is best to relax on the couch, stretch your legs out and chill and not just be all hard and tough. A lot of girls pose to mean and rough, I think a lingerie shot looks best when it is soft, sincere, like you aren't trying too hard, just being you in your lingerie, feeling sexy and desired without the pouty lips, just relax.
3. Heels! No matter your height, or size of your behind or your curves, wearing heels is a MUST for Lingerie modeling. Unless it is more of a casual wear under garment.