It’s all about wardrobe. As a best man, you will be expected to help the groom choose his tuxedo, along with those of the other groomsmen. In addition, it’s your responsibility to make sure every man in the wedding party goes to get the tuxedo fitted and picks it up in time for the big event. You will also want to have boutonnieres ready for the groomsmen on the day of the wedding.
Take care of the groomsmen. Help arrange for accommodations for any man in the wedding party who will have to stay overnight to attend the event, contact the groomsmen to help plan a gift for the groom, and keep a list of names and phone numbers to keep all the other groomsmen on time and on schedule. You are the hub of communication during this event. Keep your phone on at all times.
Make him look great. He’s nervous and his mind is anywhere but in the dressing room. Make sure his tuxedo is on, properly secured, and fits perfectly. Don’t forget his boutonnière and dust off his shoulders before he makes a grand entrance on his big day.
Take care of the small stuff. In addition to holding the rings until the ceremony, collect payments from the groom to vendors, the band, the minister, etc. so that you can distribute them appropriately after the event. You may also want to hold onto the marriage license which you will later sign as a witness.
Escort the Maid of Honor. You’ll walk down the aisle with the bride’s best friend, sister, or roommate. Be a gentleman and enjoy the stroll. Remember, this woman is taking of as many responsibilities as you are for this occasion and she is likely somewhat stressed herself.