1. Set your date as soon as you know your wanting to have a yard sale and as far as possible. Know your neighborhood; know when the large employer's in your area pay their employee's. Do you have a significantly large population of elderly or families receiving government assistance? Plan around those times and make sure you're not planning it for a holiday weekend.
2. A few weeks ahead decide what type of yard sale you want to have. Do you want to have a Church yard sale, a single family yard sale, a multi family sale or a neighborhood yard sale? Just remember, the more sellers you have the more word of mouth you get. Share in the costs and time related to the sale. Get someone to collect the money for the ads, someone else to do the flyers while others can post flyers and hang posters around town.
3. Advertise, Advertise, Advertise! If you have no plans to advertise your sale you might as well not put forth the effort of putting stuff out in your yard. Place ads in your local paper, some paper's offer yard sale listings for free. Be sure to check on their deadline date. It's so frustrating to send in your ad only to later find out you didn't get it to the publisher in time. Post on www.craigslist.com its free and very popular.
4. Put posters up everywhere, business windows, crossroads, community calendar's or anywhere that the public passes through. Make a poster to tape to your car window, be sure to park in well trafficked areas. Clearly post start time, but be prepared most seasoned yard sale shoppers believe "the early bird gets the worm" and stops in 30 minutes or so early "just in case" you have everything out and ready.
5. The week before your sale start getting ready by putting price tags on everything. Make signs for your sale such as "Everything Negotiable" or "5 Books for $1" or signs saying "After 2PM everything off". You can price everything with labels, stickers, masking tape and markers. Be sure to put the price on the top of items so it's easily seen. Price things about to 1/3 of what something might cost new. Depending on what condition your item is in will give you a better idea of how much to ask for each item. Be reasonable and know people are looking for a bargain. Take a few extra minutes to get your sale items clean and in an organized fashion.
6. Know what the lowest amount you're willing to take on an item. Have the items out so people can see what you are selling. They can't buy what they don't see. Display is important! Display your best deals in a place that will lure your customers into your sale. Put like things together for easier access. Put small items in lip lock baggies so all the pieces are together. Shoppers love "grab bags" as well.
7. If an item can't be displayed for some reason be sure you have signs up to show shoppers where the item is located such as the back yard. Balloons are a great touch and they always attract shoppers. Have an extension cord out so that people who want to buy electronic equipment can see if it really works. Know about what you are selling, if you're missing something from a package such as instructions let them know.
8. The day of the sale, be prepared by having change, calculator, pen, paper and change box. Make sure you are ready no later than the time you advertised.
9. If you are prepared your sale should go off without many problems. There are always things you didn't think about but people understand. Have fun with it. Get the kids involved by allowing them to set up a Lemonade stand or having games to occupy the kids while the parents shop. If you have the extra help have crafts available for the kids. The less the kids are pulling on the parents the more time parents are going to be willing to stay around and shop.
10. Have a plan for the unsold items. Are you going to pack them up and store then for another yard sale? Do you have extra boxes for packing them up? Are you donating them to the local thrift shop? (if you're going to donate them be sure to get a receipt for your taxes as a deduction). I've found that there are those who love to buy "what you have left" for "their" next yard sale. Have in mind a dollar amount. It's worth it just to get your unsold items carted off if you have no future yard sale plans yourself.