Keep a folder of screenshots from movies, commercials, etc. with looks that you like, and save them for use as inspiration and reference. If you can, even load them in your still-store to use as a reference in building a look.
Keeping a running folder on your computer of images that you like from movies, TV shows, commercials, music videos, etc. will give you a well of inspiration to draw on when you get stuck developing a look. Just look back though the images and see what looks good. You can compare locations, subjects, and moods to with the images to see what might work for your shot. This is especially helpful when you feel like you’ve been doing the same looks over and over, and you want to try something new that you might not have thought of on your own. Don’t feel like you have to copy exactly though. The images can serve just as well as a jumping-off point for your own variations.