This info comes from Kovels.com

Looking for extra cash? Clean out your house and run a garage sale. Better yet, join with friends and host a big, big sale. Many newspapers offer a garage sale kit to tell you what to do. Find someone who has run sales before to help you out.

A few tips: Run an ad online (Craig's list is good) and in your local paper. Read other people's ads to see what's selling. Put up neighborhood signs that can be read from a moving car. Set up a sorted display--clothes in one place, toys in another. Mark everything with masking tape or another label that's hard to remove. Do not put labels on paper or other surfaces that could be damaged by the glue. Make sure there's an electric outlet nearby that can be used to test any electrical items. Price things low enough. Your selling cost is less than it would be with a lot of online listings.

Don't let anyone in your house for any reason. Keep cash in a secure box with a trustworthy person watching it. After the sale, help others by packing up what remains and taking it to a charity resale shop. You'll be adding a good deed to the list of your accomplishments that day.

Great tips!
Do you know, does City of Alabaster requires permit for garage sale?
I know that Pelham does, and if you do not have a permit, police can close your sale up.