Hello, groom. I was in your ill-fitting, rented shoes once. I awoke on my wedding day full of confidence. Now, after five years as a wedding photographer, I realize mine was a common mistake.
Oh sure, when I think back to my own wedding day, I have no real regrets... but I wouldn't mind having been a little better prepared. Of course, the weeks leading up to the big day were filled with preparations of the typical variety: the venue, the cake, the guests, et cetera.
I thought I was pretty slick. I didn't need to worry about the ceremony itself. I had been to enough weddings to know what was what.
The result? I appeared-- ahem-- less than polished, to say the least.
It can happen to you, too! Before you get in front of a room full of friends and family-- yours, and more importantly hers-- seriously entertain the idea that you are not as cool as you think you are. Take steps to prevent embarrassment!
The rehearsal night is not the time to learn your vows. Do yourself a favor: give yourself at least a week saying these aloud before trying them in front of a crowd. Aloud, and preferably in front of a mirror (or your fiance, if you don't have a mirror).
Without preparation, unfamiliar things might come out of your mouth in the crucial moment. Or if there's a challenging, tongue-twisting passage (writing your own vows, anyone?), you need to amend it while you have the chance. It takes a lot of effort to make things sound effortless. Ask any script-writer.
For the love of heaven, practice! If you were going to sing the National Anthem at a ball game, you'd practice. This has to be at least as big a deal as that.
Good luck. You'll do fine. Even if you flub your lines, you'll be just as married. And your friends will have a hilarious story.