• Nine Weeks Before

• Determine who hosts. Will it be you alone or will you share duties with a cohost?
• Set a budget. Are you paying for it all, or are others contributing?
• Decide where to have the party. A restaurant or catering hall? Your home, or that of a friend or family member? If you need an outside venue, scout around and book it early.
• Pick a date. Consult with the honoree's mother, sisters, and best friends—especially those who'll be traveling long distances—to find a time when all can be present. Shoot for a month or two before the due date, or at least a month after the baby comes home.
• Make a guest list. Decide whether to invite women only or couples, then e-mail the honoree's closest family members and friends for a list of people they think should be invited (with phone numbers and mailing addresses—as well as e-mail addresses, if you'll be sending an Evite). Or, if the shower is not a surprise, consult with the guest of honor.

• Six Weeks Before

• Choose a theme, if you'd like. It can be traditional (baby-related) or as simple as a garden theme, with baskets of flowers and pots of wheatgrass. Keep in mind the tastes of the expectant mother.
• Send out invitations. Provide a map or directions to the location and an RSVP deadline of no later than a week before the date.
• Go shopping. Buy decorations and disposable tableware, plus party favors and goody bags (or order them online).
• Plan the menu. A brunch or tea party is traditional; a light dinner works for evening showers. Also consider finger foods, a potluck, or a dessert party. If you have a theme, the foods should reflect it. If you'll be doing the cooking, try to choose dishes that can be made a week ahead and frozen, or at least the day before.

• A Month Before

• Line up some extra hands. Arrange for cooking, serving, or bartending help or entertainment, as needed.
• Order the cake. Also, the flowers, rental chairs, etc.
• Help with thank-you notes. Print out the invitation list, with complete addresses, to give to the honoree (now, if it's not a surprise; later, if it is), or buy cards yourself and address them for her.
• Prepare some games. Stock up on whatever materials are needed to play, such as pencils.

• A Week Before

• Follow up on RSVP stragglers.
• Put together the goody bags. And if you have prizes for the games, wrap those.
• Plan to get the gifts home. Lay in a store of handled shopping bags, and use discarded wrapping paper to cushion items. If the honoree lives a plane ride away, have labeled shipping boxes and packing materials ready.
• Assign a photographer. You'll want your best shutterbug to take photos or videos.
• Clean up. If the party is at your home, give it a thorough cleaning.
• Shop and cook, if needed. If you'll be doing the cooking, buy all the nonperishables, and prepare as much freezable food as possible.

• Three Days Before

• Complete the grocery shopping. Finish up the food preparations.

• The Day Before

• Do a quick cleaning sweep. Give your house the once-over.
• Set up the party space. Arrange the furniture. Put out the favors, prizes, and games, and check to make sure you have everything you need. Set out trash bags where the gifts will be opened. And decorate.

• On Party Day

• Pick up the cake. Also the balloons, flowers, whatever.
• Designate someone to help the honree. She'll need a hand to record the gifts and the givers.
• Original checklist at realsimple.com