It's really hard to judge prices on things. Like say you want 5$ for an item, one person asks you and you say 5, they'll counter at 3. If you said 7, they'd counter at 5. The other person, if you said 7, might not even try to counter and just put it back, but might've purchased it at 5.
It's an evil game, which can get frustrating. But my rule is, I'm not going to give a good product to some one for a quarter because they think they can nickel and dime me, I would've just saved my time and donated it to goodwill. When all I'm asking for is a dollar or two.
As far as set up goes, I set my stuff up the night before (in the carport) and moved all the tables to the corner with a blanket over top. Then I just pulled the tables out in the morning. Being up at the crack of dawn is always a good start. If you've got a keurig machine, you can give away fresh cups of coffee for 50-75 cents. Cold drinks are also a nice seller in warm weather. I had some soda, capri suns, and bottled water, which could all be used even after the sale.
For my signs, well the big one on the major street. I took a box, flattened it, and taped it across the top. Then I bought some of the sample oops paint from lowe's for 50 cents, and painted Yard Sale in green with a beige background. It wasn't glaring neon where you can't see the thin sharpie lines. But still bright enough to be seen in time for people to make the turn. Then I hung it over a metal for sale sign a neighbor gave me. In the front yard, I used the little signs from Home Depot with the metal stakes. I did learn the hard way with the Dallas winds... to tape the signs to the stakes because they can blow out. I also put a pot of fake flowers underneath the sign to make it more noticeable. And even though I had the sale in the carport, which was in the alley, I had plenty of signs to lead the way. This also helped keep everything in the shade. People stay longer when they're not sweating up a storm.
If you have really hard dirt, pour a pitcher of water in the ground and let it soak up before trying to put the stake in. It really helps get it down into the ground and hold it all day.
For tables, I got lucky because the last home owner (my aunt was downsizing from moving into a new home) had those plastic heavy duty storage shelves in the outside closet. Some of them I left 2 or 3 high, with the others just 1 high. I also used things we were selling as tables, like the coffee and side table, the nightstand, the desk. I also clearly marked them with a price so people new they were for sale as well.
Clothes and a couple blankets were put on a clothes rack. This was borrowed from a family member who just so happened to have one for her own sales. But I had a lot of people browsing the clothes this way. Easy to check the tags, and see the garment. Framed pictures were hung on the fence so they were at eye level.
Ohh yeah, and watch the neighborhood for the days people put up yard sales. In Texas, I did best on Friday and Saturday, Sundays were always a bust. I figured more people might show up to get in the late bargain, but nope. You kinda want to jump on the bandwagon with this, because this is when shoppers are out searching for those signs. You do it on an off day, and you're not going to have those shoppers looking. Check craig's list and post your own ad there too. I took a few pictures of larger items and listed them with my garage sale ad, so there was something a bit more to entice people with. On my first day, I had a few people show up looking for specific things that I had listed.