Retouching
Seriously, if you have a shoot booked with a professional I'd be apalled if they didn't retouch them and get rid of your cellulite, smoothing skin is easy. If they don't retouch ask for hi res images and google for a retoucher - India usually does them for a couple of dollars a picture IME.
Other than make sure you're well moisturised and don't have dry skin, manicured and pedicured nails, good hair, good base (quite thick but you don't want it to cake) fake lashes, and I used some benefit bathina oh so fine body shimmer, you can also use baby oil to make you glisten a bit/a lot depending on what you want to look like, but check with your photographer.
Oh and fishnets always make your bare legs look good under knickers.