Garage sales are probably one of the most popular ways to make extra money. Depending on what you have to sell, sometimes alot of money can be made. That being said here are a few suggestions:
1. ADVERTISE!!!! There are several ways to advertise for free. Craigslist has a garage sale section. Put up flyers, make posters and signs. Some home owner associations allow for free ads in their newsletter.
2. Schedule at the first of the month. People shop more around pay day!!
3. Make sure your items are neat and clean. No one will buy dirty clothes.
4. Sell it! Sometimes people want to haggle to a really cheap price. Remember any money you make is more than you had.