Garbage bag: Caught in a sudden downpour while shooting? Use a garbage bag to cover up. If you really want to keep shooting, punch a whole big enough for your lens you've got a raincoat for your camera. Aside from this, you can spread the bag on damp ground to kneel, sit, or lie on.
Clips and clamps:** Need to make your model's outfit fit better? Tighten it with a butterfly clip.
Duct tape and masking tape:** If something moves when it shouldn't, you need to tape it down – that's only the beginning though. Use it to cover a window with white sheets, or to stretch a cloth background taut. Don't forget - you can also mark your model's place with a bit of tape.
Adhesive Clay:** If it's too small to tape down, don't worry – that's what adhesive clay is for. It keeps mirrors, reflectors, and other little things in place while you shoot.