Preparation

Set up a staging area where you will assemble everything for the sale so they don't get mixed up with your other belongings.

Go through all of your belongings, not just those that you've been thinking about selling. Antiques are always good items, no matter their condition. Don't throw anything away. As they say, "One person's trash is another person's treasure." I know one person who got her boyfriend at a yard sale for 50 cents ;-) Plus you can always throw the item out after the sale if it doesn't sell.

In keeping with not throwing anything away, have a free box or section for those items you don't think will sell. You can even advertise that there are free things. It may make sense to have decent items for free so you can advertise free stuff. That should increase the number of visitors. The more visitors you have the more likely you'll have buyers for your items.

Also collect whatever tables you will use to display small items.

Have bags for people to carry their purchases in.

A calculator is always handy. And when there is a language barrier, it can be used to show a price, even back and forth while bargaining.

Plan to display things off the ground if possible. Otherwise use tarps or sheets to display items on.

Clean and repair whatever you plan to. Clean items will display and sell better. Run kitchen stuff through the dishwasher. Wash clothes so they are fresh smelling. Clean dust and dirt off of everything.

Know what items work or what items don't. Answering "I don't know" when asked "Does this work" won't make a sale, but people will be things that don't work if the price is right and they can fix them.

Know if parts are missing.

Price items. Many people will haggle over prices, but having a starting point already in mind when someone approaches you will make things easier. Plus, some people may be shy about approaching.

Keep prices simple. Don't do the store thing and price something of $9.99. Simple prices keeps the math simple too.

Price items, except antiques and collectables, around 1/4 to 1/3 their retail price.

Be prepared to bargain over prices and be offered very low amounts for items.

Price stickers makes it easier. If you use stickers, you can collect the stickers when you sell things to keep track. If you are doing the yard sale with others, you can use different color stickers for each person's items to make the splitting of money easier.

If you have lots of items, each for the same price, consider having a table for those items, like the $1 table and so forth.

If you are unsure of the reasonable values of items that may be worth something, get them appraised, or check online for fair market values of similar items, by checking on Ebay or some similar resource. Otherwise, have some idea of what is reasonable in your area. Even visit some garage sales in the preceeding weekends to see what other people sell stuff for.

Price set items as sets, such as four glasses for a dollar. Or offer bulk deals - $1 each or 7 for $5.

Consider having a FREE box for items that are free. And advertise it on your signs, if they are decent items, such as paperback books.

Get plenty of change, both bills and coins. Have a cash box, or even better, a fanny pack or belt pouch that is always on you to keep money in. Having a dedicated cashier can also help during busy times. DO NOT LEAVE YOUR MONEY AT ANY TIME.

Prepare the area where you will hold the sale. Make sure there is nothing people can stumble, trip, or slip on. Mark rocks, sprinkler heads and such. People will be looking at your items and not necessarily where they are stepping.

Determine how you will lay everything out ahead of time. Make sure that there is plenty of room for displaying items and having lots of people milling about.

Make sure everything is on display. People won't dig in boxes too much. And when they do, they expect to pay less than displayed items.

Keep valuable items, particularly if they are small, either near you or where you can easily keep an eye on them at all times.

Make sure fragile items can be displayed away from young hands. Youngsters are curious and parents are checking out your wares and can't keep an eye on their kids every moment.

Put up a clothesline to display clothes.

If you will hold the sale in any part in your garage, carport, or any area where there are items not for sale, ensure that it is obvious what is not for sale. Cover them with tarps or sheets, so they don't even come into question.

If you have any electrical items, have an electrical source handy to let people test them. If you use an extension cord, use a heavy duty one. Make sure it is out of the way so no one can trip on it.

Have batteries to use for people to test things that require batteries. And make sure to remove the batteries after testing, if you have other battery operated items.

You will invariably have leftovers. Decide what you will do with them and make preparations ahead of the sale. Don't keep them for next year's sale. If they didn't sell, there's a good chance they won't sell next time.