You are already pretty lean so the adjustments to diet or doing fasting will make the biggest difference. I would look at dry steroids like masteron, primo, anavar, and other compounds like Cardarine.
For the amount of different SARMs you will stack and take to achieve significant changes, you could just as easily hop on some low dose clen + anavar leading up to your photoshoot, make sure to use a trusted source such as pctshop.com so you do not take any chances with virlization when it comes to using steroids as a woman!