These are some of the things I've learned hosting my Thanksgivings potlucks outdoors for a large gathering:
• Invitations: Send online invitations so people can respond at a common site, such as Evite, Pingg and Crusher, and indicate which dish they'll be bringing. This is a great way for both you and your guests to keep a running tally of what you will have and what is still needed. Many online invitations offer specific potluck options in which you indicate what you need, and guests check items off the list.
• Safety: Food can cool quickly if kept outdoors. Have guests bring dishes that are not temperature-sensitive. Or for sensitive foods, be sure to keep space in your kitchen (a warm oven for warm dishes, and plenty of refrigerator space for cold).
• Do-Ahead: Have your guests prepare the dishes before they arrive so you don't have to worry about providing cooking space and related cleanup.
• Stocking up: Depending on the size of your party, have each of your guests bring enough of a dish for at least six to eight servings. You may want to have more than one guest cover staples, such as mashed potatoes, that everyone will want. Ask guests to bring more side dishes than desserts, and be sure some of the guests bring light dishes, such as salads.
• Setting the table: Get a rough head count as soon as you can, and place your order for linens and other place settings with a party supply company as far in advance as possible to ensure you can reserve the number of items you need. Plan to rent a few extra chairs, just in case.
• Serving spoons and utensils: Guests may not bring a serving spoon or utensil to go with their dish. Keep extras on hand. If needed, you can rent these from your party supply company or buy inexpensive servingware at restaurant supply companies.
• Glassware, plates and silverware: Consider whether you want formal or disposable. You can rent china and glassware from a party supply company or purchase disposable items from a party store — a big plus with disposable is you do not have to wash anything, and you don't have to worry about breakage. Finally, be sure you have plenty of silverware — you will need things like forks for dinner and dessert.
• Beverages and ice chests: Have guests bring a beverage along with their dish. Be sure to have water and sodas on hand, and plenty of ice. Buy your ice early in the day, before things get crazy, and stock up your ice chests (chill sodas and water, extra ice for drinks).
• Cleanup: No one wants to clean up after a party, much less a big dinner. Have plenty of trash cans available during the event, and give yourself some time the next morning to allow for cleanup.