Set a date. Do this well in advance. Don't choose a holiday weekend, and pray for good weather.
Decide what to sell. In addition to the things you've collected from purging, give everyone in your family a box or two that they can fill with additional items they are ready to sell.
Collect sale items. Sort and box similar items. This will save time later when you are setting up. Store everything neatly in the garage.
Tell your neighbors. Let your neighbors know about the sale, and encourage them to sell on the same day. The more sellers, the more people you'll attract.
Tell the world. It's all about advertising. Put large, colorful signs on a major road. Keep them all the same color with clear directions, the address and the time. Also, take out ads in local papers and put notices in local supermarkets. Try listing the yard sale online or in free community papers also.
Attach price tags. Clearly price everything with masking tape and bright markers. Put like things together. Use tables to make the viewing of merchandise easier. Borrow clothing racks, and have a great layout of goods so people can easily see everything.
Enlist helpers. Assign your helpers specific tasks like managing the crowds, answering questions, making sales, taking payments and providing laughter and fun.
Be prepared. Have an extension cord handy so people can check electric items. Have shopping bags or boxes handy to help people collect and carry goods away.
Get some sleep. On the night before the sale, put up a sign in front of your house that says, "Absolutely no early birds." Otherwise, you'll have people knocking at your door before the sun is up.
Manage the money. Have a lot of small change handy—use a fanny pack to keep it safe and in one place.
Bargain. The idea of a yard sale is to get rid of everything. Bargain like crazy—offer to add items for an extra 50 cents or offer five books for the price of three. An hour before closing, slash prices!
Get rid of everything. Arrange for a charity to pick up whatever is not sold. Don't take anything back into the house!
Above all... Keep your sense of humor and make the day enjoyable for all. Encourage people to haggle and make a game of it. You'll sell more stuff and have fun.