1. Manage the family.
If you know that certain relatives get on your daughter's nerves, don't insist she include them in everything on the wedding day. She needs some time and space to get ready without any drama or stress. Be the bouncer on your daughter's bridal suite and keep the wolves at bay until after she's gone down the aisle.
2. Marshall the boys.
That includes your husband if you're married to the bride's father. And even if you're divorced, as long as things aren't acrimonious, try to keep him on schedule too. Work with the groom's mother to make sure all the gentlemen will be dressed and ready to go at the appointed time so that the bride doesn't have to worry about it.
3. Be sure the bridal party is eating.
They're going to be drinking (champagne or some other concoction) and it's easy for them to get tipsy on empty stomachs. Not cute on the wedding day before the ceremony. Plan ahead with your daughter to have food and soft beverages available for the ladies so that they can have something in their tummies.
4. Have your own act together.
Don't bring two dresses and ask the bride to choose for you at the last minute, she doesn't need that additional mental challenge. The biggest gift you can give her is to be easy, organized and ready so that if she needs extra hands or help, you're already dressed to go and you can be there to help your daughter.
5. Be the voice of reason.
If something goes wrong, stay calm as you try to correct it. Things go wrong and as the mother of the bride, some of it will come to your attention. The problem is there are some things that might not be able to be fixed — such as the florist delivering the wrong flowers just before the ceremony. Instead of getting upset about it with your daughter, tell her how unimportant the detail is in the grand scope of things and how you'll laugh about it later. Minimize problems and help her focus on the good things happening around her.
The most important thing a mother of the bride can do on her daughter's wedding day is to just be there for her, completely and selflessly. You're her mom, and she needs you.