1 week before: Get stuff "sale ready" by cleaning items and making them appear that they came from a well cared for home and are therefore going to look more tempting to the buyers. Organize items by category, such as KITCHEN, CLOTHES, TOYS, ENTERTAINMENT, etc. Get plenty of paper or grocery store plastic type bags ready to have available to buyers. Have bubble wrap on hand for anything breakable!
A couple days ahead: List on Craigslist, including several of the most sought after items so people are enticed. Hang signs in the neighborhood. Advertise in local paper. Send an email to your friends and ask them to spread the word. Do you have a community website where you can post? If so, that is a place to post! Purchase poster boards for signs to note Half Price or All items $1.00 when the end of the sale is approaching and you want to get stuff moved. Go to the bank and get SMALL BILLS. Get at least $100 in smaller bills--4 $10, 5 $5, 25 $1 and $10 of quarters. You don't want to lose ANY sales at all, and surely none that are because of not having the right change.
The morning of: Set up the items, attractively displayed, and set your cash station. (Be sure to have the cash station in your sight at all times, or the siight of one of your helpers). Allow plenty of time for set up. Offering free lemonade is a nice touch and be sure to have pleasant background music that would have a broad range of appeal--Sinatra or Classical are both good. Wear an outfit with POCKETS to stash exact change sales so you don't have to take time running over to the cash station each time. As you get closer to the the end of the sale and you see traffic lightening, consider posting a sign saying HALF OFF or EVERYTHING ON THIS TABLE $1.00. Make signs up that morning ahead of the start of the sale so you have them ready to go. Stash them safely inside the house so they don't get mixed into things and cause confusion with buyers. Have a bottle of water and a back up bottle ready for yourself so you don't need to run inside when you get thirsty.
At the end of the sale: Pack up leftover goods in boxes and/or bags for charity pick up.
After the sale: Congratulate yourself on a job well done. Your purging has produced some extra money and your no longer needed items are now in homes where they can be used and enjoyed.