You might think that this is too obvious but trust me, if you forget something you can have a big problem, so is better to have a check list and be sure that everything is ready.

- Charge your batteries. This not only includes the batteries for your camera. We use a lot of equipment (power packs for strobes and flashes, triggers and receivers, monitor if you shoot video, flashes, etc.) and running out of batteries in any of them is a nightmare.

For the camera, I always take at least four batteries, and I always carry enough batteries to change the batteries of all my flashes and receivers at least once. (Think about the extra waste of battery when using Live View).

- Check flashes and receivers. Take one shot with each of them. Sometimes you change something by mistake (like the channel in a receiver) and suddenly it doesn't work anymore. It's better to check these things at home rather than wasting time during the shooting.

- Format the memory cards. If you do it right before the shooting and suddenly find out that you still have pictures on a card that you didn't previously download, you will spend a lot of time or capacity on your cards.

- Check your camera setup. Maybe for the last shooting, you set it up your camera in a specific way (white balance, picture format, etc.). If you forget it and start taking pictures, you can end up having pictures in low resolution, high ISO, etc.

Don't forget to set all your lenses on autofocus!

My standard setup is RAW, 100 ISO, AWB, Manual Mode, Highlights alert on, preview with histogram, focus beep off and silence shooting mode for events.

- Clean your lens. I take my camera and lenses to the Canon official service center every 6 months for a deep cleaning, including sensor. But for minor stains like water drop marks in the lens, I do the cleaning by myself. If you don't check it, you may end up wasting a lot of time later with Photoshop.

- Choose the corresponding equipment for every specific case. Obvious? Packing 5 minutes prior to leaving can be risky. Try to imagine all the situations that you could find yourself in during the shooting, and pack a few hours in advance (if you can). Even if you think that you will not need it, always take the chargers, card reader and laptop with you.