Expect the unexpected.
Fly by the seat of your pants.
Be prepared for anything.
Weather, lighting and equipment malfunction are all part of photography. I can plan for and choose a location only to have a truck pull into the background as soon as I begin to shoot. The beauty of the situation is being resourceful, using your own initiative and perceptions along with a pre-determined plan. During an amazing wedding Sunday, one of my flashes just stopped working! I spent a couple of minutes checking batteries, connections and turning it on and off. Dead. I threw it in the bag, grabbed on of my backup flashes and kept shooting. Before the ceremony I raised my flash up high, it hit a ceiling fan, broke an attachment, grabbed a backup and kept shooting!
Will be more careful with a flash in a room with a ceiling fan when you are 6' 3"... Check!
BTW here are some pics from the wedding! Congrats Brittany and Sean!