The day before your shoot, charge your batteries for your camera and microphones. Days before, make sure you have all the equipment you need, giving yourself time to borrow, buy, or rent what you need. Do you have several SD cards? Does the camera fit onto the tripod (do you have the necessary plate that fits?) Do you have a stand for your light, and something to soften the light? How about headphones? Pack two extension cables with power strips (multiple outlets on a strip).
If you are new to shooting or rusty, practice shooting at home, and playing back what you shot. Test to make sure your audio is working, using headphones. Practice setting up your gear more quickly. (These tips do not include how to use the settings on your camera, because there are many such guides, and they are usually specific to your camera.)
For more about what kind of gear you need for shooting with a DSLR or iPhone, contact Lisa at firstname.lastname@example.org.