Head her off by asking for her help in small, specific ways -- such as deciding on the seating arrangements for her family's tables or designing a groom's cake with her son, suggests Elise Mac Adam, author of "Something New: Wedding Etiquette for Rule Breakers, Traditionalists, and Everyone in Between" (Simon Spotlight Entertainment; 2008). "If you didn't plan on a groom's cake, this might be the moment to consider it," notes Mac Adam. And remember, if your future in-laws are hosting the rehearsal dinner, your mother-in-law automatically gets as much control over it as she wants.

Very seldom is money given without strings -- even when people say "no strings attached." The best course is to find out what the expectations are before the offer is accepted.

Be sure to ask the contributors exactly what they want to pay for. And remember that the creative control remains with the wedding's host. Your groom's parents don't get to pick the flowers or the florist; it's not even necessary to brief them on your decisions.

And the fact that they're helping doesn't guarantee them a spot on the invitation, but if their contribution is significant in scale, it would be a smart move to list them.

First, express your gratitude. Then, explain your preferences in a non-defensive way. "If you emphasize how pleased you are, it will be easier for people to see why you like the things you do," says Mac Adam. Then try to compromise. If you want 40 guests and they want 150, pick a number in between. If you're set on a simple wedding and they want something more elaborate, Mac Adam suggests giving your parents free rein over some creative elements, such as the invitations.

If the list is loaded with so many of their invitees that there's little room for yours, offer to contribute some of your own money in order to include more of your friends. If all else fails, though, you'll need to let them do it their way, unfortunately -- or foot the bill yourselves.

The customs of the two different families need to be clearly communicated. But those who are actually hosting -- defined as a combination of "footing the bill" and "making the decisions" -- hold absolute sway in defining the hospitality that will be offered. And it is completely rude to insist that someone else follow your own hosting instincts or pattern (doubly so when that would also involve them spending more money).

The family that wants a more elaborate event is free to host a follow-up or additional event. However, if the bride's family's wedding reception is deemed to be not-quite-adequate, the groom's family cannot host an alternate reception, but they can certainly offer additional hospitality to family and friends at some other time.

Today, most people believe the couple should pay for their own wedding, especially if they have lived on their own for a time. Of course parents often want to pitch in too; negotiate who contributes according to their willingness and their ability. Get more information and a breakdown of traditional roles here.

Though the oldest of invitation etiquette leaves stepparents off the invitation completely, today's expectations side with including them, even if you aren't particularly close. See more information on invitation wording for specific suggestions.

If the bride wants to include her stepfather in walking her down the aisle, one common solution is for her father to walk the bride partway down the aisle, handing her off to the stepfather. Other brides have asked both men to escort her.

The father of the bride normally welcomes guests to the reception, which is his role as host. Unless the stepfather's hosting role is primary, he should be willing to take a back seat here.

If a bride or groom is going to dance with a parent, it's not required that she also dance with the stepparent, but if they are at all close, it would be good to do so.

It's quite common nowadays for each household (father and stepmother; mother and stepfather) to "host" their own table; this spreads the family attention around to many guests, and it reduces possible tensions between them. You can arrange them near one another or farther away, depending on the emotions involved.

It would probably be best to buy everyone invovled corsages or boutonnieres whether they're married or dating. One firm rule of etiquette is that couples who are a "social unit" (married, engaged, living together) must be treated as such. Disregarding this rule at a wedding could create some bad karma -- and some hurt feelings. It's perfectly appropriate to give these new partners a less flashy corsage or boutonniere than your birth parents (as long as they're not the only ones getting them). Emily Bouchard, a family therapist, coach, and founder of Blended-Families.com says, "You should come from a place of respect rather than basing your decision on liking or disliking someone."

If this will be difficult for you, discuss your dilemma with your parents before deciding. Their input will help you avoid a major fallout on the day that is so important to you.

If this is a sincere worry, sit down with each woman individually, and make a personal appeal. "This is an important day for me, and I'm going to be very emotional. I need to ask you to put aside your animosity for this event, and for all events surrounding it. If you love me, please promise me that you will be polite and civil."

In the case of your stepmother, you can also share your worries with your father, and ask him to make the case for pleasantness to his wife.

Then recruit someone (your wedding planner or a bridesmaid) to be on "mom patrol;" if one of the women forgets her promise, her "minder" will be prepared to take her aside and ask her to refrain from unpleasantness for your sake, and for the sake of all your guests.

Seek the help of a third party. "Ask her to join you for an afternoon of shopping, and use a personal shopper or sales consultant to take the pressure off," says Karen Bussen, author of "Simple Stunning Wedding Etiquette" (Stewart, Tabori & Chang; 2008).

She'll be more likely to accept fashion advice from a professional. If she still ends up picking something completely hideous, keep your disappointment to yourself: "In the end, a happy mother, wearing what makes her feel great, is much more important than a perfect photo opportunity," says Bussen.