Check List

Charge your batteries, and the spares!
Clean your lenses, wipe them down and use lens cleaner to get everything spiffy.
Decide what items you will be taking with you and what you’ll be leaving behind.
Pack your gear and make a list on a 3×5 card of everything you will have. That way you can check against that at the end of the day to make sure you return home with everything you took in.
Check the weather beforehand and plan your clothing accordingly. This also means perhaps including some protective elements like towels and such for your camera gear in case there is a chance of rain.
Get a good nights sleep.
Verify the starting time and place for the shoot.
Print out a map of how to get there, especially if the location is unfamiliar to you.
Pack a few munchies (granola bars, pretzels, etc.) and maybe a bottle of water or two.
Have fun!