Decide on a date. Organize all of your garage sale items and put them into one area.
Every item needs to have a price tag.
Display all items on tables, etc. Get change from the bank, particularly fives, ones, and change. Decide on a safe place to keep money. Put signs around your neighborhood on the morning of the sale advertising the sale and make sure you take them down when your sale is over. If you don't want people showing up at your door early, specify no early birds in your ad.