I have catered over the years and weddings scare the bejeebers out of me, I have also shot video at weddings. You only get one shot to get it right, it is incredibly important to many people, they will not understand if you blow it, the time table is often difficult as folks are partying and not inclined to stick to a schedule. I have cooked on my own cooker and on others cookers (sometimes you just have no choice). It is not something I would recommend a novice in catering take on. And for the record, cooking for a Superbowl party or a bunch of friends at a house party is not the same.
That being said, organization is the key, I start preparing for a wedding cook weeks ahead, I start assembling my gear at least one week ahead and revisit the gear often. I make sure I have all the seasonings ready to go, make sure I have the food ordered at least a week in advance (and paid for). If I am working in someone else's kitchen, I arrange to visit the day before, drop my gear and settings at that time and make sure I know the layout.
Finally, if I am cooking, I am not a part of the party, I dress for cooking, I work on the food and I make sure things work out. I do maybe two or three parties a year anymore, I refuse all religious and wedding events and I still find it stressful. I wish you good luck if you take this on.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."