What should you do if your the Best Man in a Wedding? Well here are some basic guidelines to follow.

Pre-Wedding
Are you from out of town? If so you may need to take care of your own lodging and transportation. You could also pay for your own tux. Because of the logistics of getting the tux with the groom. However, if you are in a close proximity to the groom then you should be the one to handle the tuxedos! This includes going to the rental shop to pick them up and also distributing them to the wedding party. And don't forget your responsibility involved with the Bachelor Party. Show the groom a good time, but not too good a time.

Wedding Day
Here are the quick tips to remember
Take care of the groom. Help get him dressed. Nothing like a tie that won't tie.

Get those last minute errands done. The groom will always forget something.

You have a counterpart in the wedding party, the maid of honor can be your best friend.

If its a large wedding but not a large wedding party, lend a hand with the ushering.

Don't forget the ring. Its your single most important job!

Wedding Reception
The groom may give you money or payments to pay the minister,organist or others assorted with services. If there is a wedding coordinator they may take on this role. The best man may be asked to drive the wedding party to the reception site.
Sign that marriage license!
At the reception stay close to the groom until after the receiving line. You arent required to be in the line. However, the groom may still have something to be taken care of. After the reception collect all the tuxedos and return them to the rental shop. And if need be help with the cleanup of the reception site.