I’ve been ‘best man’ twice (and an usher three times, and an M.C. nine times…).
Duties of the best man start with the bachelor party. You need to get a list of friends/family/co-workers and - this is of prime importance - make sure EVERYONE gets invited that might be attending the actual wedding. Anyone not invited to the ceremony is optional, of course, but anyone actually going to be at the wedding must be invited. It’s an ettiquette thing.
Beyond that, your job is to keep the groom functioning on the big day. You should make sure that someone is around who knows how to tie a bow tie, which way up a cummerbund is worn, how to adjust the length on the suspenders, etc. It is surprising how many grown men do not know these things.
Make sure the groom eats something. A lot of guys get nervous stomaches, and don’t want to eat, but it’s important that they get something in them. A piece of toast, an apple, whatever. They’ll need the energy, and you can get dizzy pretty easy on an empty gut.
Then, just be there and - and this is important - be in a good mood. Laugh, smile, help ease cares and concerns. Sometimes, you can act as a buffer between an overly-excited relative or friend and the groom. Keep a level head, and try not to let too many worries land on your buddy.
You’ll probably be the witness (along with the maid/matron of honour). This means you’ve gotta sign the legal document certifying the marriage took place. The preist/minister/justice will step you through that.
And at the reception, keep a level head until after the speeches. There’ll be plenty of time to party, drink and dance after the words have been spoken.
As for your speech, there are two standard options. If you know the Bride reasonably well, you can welcome her to the Groom’s circle of friends, usually with an amusing story followed by a sincere well-wishing. If you don’t know her that well, you can try the “I’ve known the groom for years, and I’ve never seen him happier than since he’s been with you” kind of thing. It’s always good to throw in a few jabs at the groom. It’s expected of a best man.
Hope this helps. Let me know if you’re an M.C. as well. A lot of Best Men do double duty.
thwartme