1. Check with your city government to see if you need a permit or license.
2. See if neighbors want to participate and have a "block" or neighborhood yard sale to attract more visitors (and cut the advertising costs).
3. Advertise. put an ad in free classified papers, and put up signs and balloons at major intersections and in stores near your home.
4. Price items ahead of time and attach prices with removable stickers. Remember, yard sales are supposed to be bargains, so don't try to sell anything of significant value this way (that's what Ebay.com is for).
5. Check items before the sale to be sure you have'nt included something by mistake.
6. Keep pets away from the sale.
7. Display everything neatly and individually so customers don't have to dig through boxes.
8. Have an electrical outlet so buyers can test appliances.
9. Have plenty of bags and newspaper for wrapping fragile items.
10. Get enough change, and keep a close eye on your cash.