Thoroughly impressed that you made $800!! There was a yard sale thread a couple weeks ago, you should drop in and leave some tips.
@MinnieSweetheart saw my post in the Destash thread and asked me to post here. I'm certainly no expert (this was only my third garage sale ever) but here are my tips. I apologize in advance for the long post
1. If you want to do a real life yard sale instead of an online one, make sure you save up some stuff until you have a fair amount to sell. Bonus points for having larger items because they attract the eye a lot more than seeing tables with small knickknacks. Extra bonus points if you have multiple families together - you can advertise as a multi-family sale, which will entice people with limited time. As a garage sale shopper, if I pull up and only see a few items I drive away because it's usually not worth my time. Having lots of items also equals a more profitable income per hour. Setting up signs, advertising, etc all take the same amount of time whether you have 10 things to sell or 200, but with 200 maybe you'll make $500 in 5 hours instead of $50 in 5 hours!
1a. If you a doing a multi-family sale, make sure you figure out IN ADVANCE how you are going to handle money. I recommend different colors of stickers and a dedicated cashier who can record the sales. I do NOT recommend making the customers go to different cashiers for each family because that will annoy them.
2. Don't be discouraged if something doesn't sell, and don't be overconfident if something sells very quickly. Yard sales are reliant on the whims of the shoppers. I sold a bunch of clothes last time, so I thought I'd do well this time. I even lowered the price. Nope! I only sold a couple of items. I couldn't even sell the brand new $50 jeans for $2!

But last time I didn't sell a single book and this time I sold ALL.OF.THEM. Go figure.
3. To the maximum extent possible, have everything ready to go when you open. In my area garage sales start EARLY (5am is not uncommon) and people are lining up to buy at opening. Since I am doing everything on my own, I don't have time to price things during the sale. Spend the week prior to the sale pre-labeling everything. If you have a standard price like $2 for all clothes, make a large sign and post it. People will still ask occasionally ("Even this one?" "Yes, all of them are $2") but it will at least minimize the questions.
I just need to unload all this stuff I have been hoarding for years, running out of room and I hate the clutter.
4. If you are in it for the money, price in accordance with the price lists you'll find online. If you are in it to get rid of stuff, price stuff lowwwww. The guides I saw said $2-3 for CDs and $5 for DVDs. I priced CDs at 50 cents and DVDs at $1 and sold every one. Because stuff was priced low, many people didn't even bother to negotiate which I
LOVED avoiding because I'm an introvert. Some people will bargain over anything, though (see #8 below!).
I am SUPER happy if I don't have to bend over all the time to get something off the ground
5. Beg-borrow-and-steal tables and flat surfaces. If the tables aren't for sale, mark them
very clearly (although people will still ask "Are you sure it isn't for sale?) but having elevated surfaces is a must. In a pinch, put stuff on top of empty boxes. More bonus points for covering the boxes in a nice tablecloth or fabric so it looks better. Tarps work well too. If the tables are for sale, have a backup plan for where to put stuff when they sell.
Just remember that Yard Sale shoppers want "rock bottom" prices, so unless you are willing to do all the work and sell your stuff for rock bottom prices, then a yard sale might not be for you.
I have much better luck with Craig's List and Facebook Yard Sale Pages, especially for pricier items. People won't come to you for individual items of clothing, but they will for lots. It won't necessarily get rid of things as fast, but what one lady does on the "Destash" thread (which you should totally join us on) is lists 5-10 items a week on Craig's List and eBay. Then the next week, she bumps whatever didn't sell and adds items to hit her limit. If you start by just trying to sell 5 items a week, you will make very notable progress within a couple of weeks.
6. I advertised my sale on Facebook and Craigslist. I didn't say people could buy early, but I posted pictures and instantly had people asking to buy. I sold many of the larger items at full asking price this way (I didn't advertise or photograph the small stuff). I had $450 in sales in one day! That was pretty cool. Plus it meant some of the awkwardly large items were out of the way and customers weren't bothered by people moving furniture around.
I haven't had a yard sale in years, but I post lots of items on my local Facebook garage sale pages or kids only pages depending on the items. Clothing I like to sell as a lot, but will post it with a lot price and then an individual item price. I usually price items slightly higher than my bottom number, so there's roo. To negotiate. Bigger items/more expensive items also get listed on Craigslist.
Good luck! These pages allow me to get rid of items as I come across them and keep them from takin up spec in my house. Always meet people in a public place. If it's a large item and they must come to my home to pickup, I make sure not to be alone.
7. I had a "want to get this price" list, a "minimum price" list, and then the actual price I listed which was usually about 10% over the "want to get" price. As a result, even after all negotiations I made $20 more than my "want to get" total. Pretty sweet! I ONLY did this for the large/expensive items. For small items it's not worth the trouble. I recommend being exceedingly flexible on the price for small items. I often give them for free or .25-$1 to avoid the hassle and get rid of clutter.
I totally agree about posting on facebook rather than having a yard sale! Yard sale shoppers drive me insane- I can't stand people trying to chew me down on things-I post something dirt cheap and then you want to bargain with me? I had something 1.00 and this lady was trying to get me to go to a quarter- I finally said "lady I will smash this on the ground before I sell it for a quarter"
I have done great with all the facebook buy and sell sites- have only had one person try to bargain me down on an item. I just recently sold my daughters old northface jacket for 50.00 on a buy and sell site- at a garage sale someone would want it for 5.00!
8. Some people will try to get you down in price literally no matter how low you go. I had a brand new, still in package, tablecloth with the original $40 price tag still on it. It was marked $3. The most annoying customer today who tried to lowball me on every single thing said "will you go lower?" I said "No. It's brand new and more than 90% off. I want $3." He said "What about $1?" No, dude! Go away! The tax write off is worth way more than that!
Additional:
9. Don't forget about tax write offs! Some things are better to donate, especially if you can't get a good price. I wanted to donate all of my books but the library here won't take used books which is ridiculous because the libraries barely have any books and they are all OLD. So, I was happy to sell them finally. But I have a couch nobody will buy despite the good condition and low price. So I'll donate it and get the tax write off which is worth more than I can sell it for. And, they'll pick it up! And, a charity gets it for free!
10. If you are serious about getting rid of clutter, have a plan to donate it after the sale. I finished the sale today and by 3pm everything leftover was packed in boxes to go to Goodwill.
11. Last time I used 8x10 poster board signs to label groupings and had lots of price questions. This time I used 24x36 pieces of paper and had far fewer questions. I guess when people saw prices in large letters they knew I meant it?
12. I had today's moving sale indoors, and a lot of people really appreciated that. Now, mine was a moving sale so basically everything else was already out of the house. This wouldn't work for most sales. But if you can do this, I recommend it! People were willing to spend time browsing instead of hurrying back to the air conditioned car. I had HUGE signs outside my house that said "THE SALE IS INSIDE" and also advertised on Facebook and Craigslist that this would be an air conditioned sale.
13. Several websites with garage sale tips recommended having free snacks and drinks for paying customers, so I tried that. What a waste. I only got rid of 4 snacks and 8 bottles of water. Now, that is a problem since I'm packing up the car and leaving town soon! I have a bunch of food and drinks to get rid of. It wouldn't have been as big of a problem if I were having a normal garage sale, but again I'm leaving so it's annoying. And honestly - I can't give away food and water?? ***? Save the money. At most buy a $3 case of water at Costco and have that, but again only 8 people took me up on the offer.
14. What you can give away is a free pile - since my sale was indoors I had a whole room dedicated to this. People won't buy old magazines for a nickel, but if they are free they will take them away by the armful. It's also a great way to drum up interest - have a prominent
"FREE" sign to get people out of the car and into the sale! Again, if you are trying to get rid of clutter this is a great way to get rid of all those worthless items that aren't worth driving to Goodwill. It's amazing what some people will get excited about getting for free. Used hand towels? VHS tapes? Empty CD cases? People love them. Who knew?
15. Groupings! Make sure you group like items. I hate when things aren't grouped. I had a pet area, holiday area, kitchen area, sports-and-rec area, etc.
16. Use matching bright colored signs to advertise. Mine were neon yellow. When you post on Craigslist, include a comment like "Follow the bright yellow signs!" There are still a lot of people who don't use map programs on their phone and really NEED those signs.
Yikes, that was long. I hope it helps somebody!