I hate doing garage sales. If I go to a garage sale, I won't look twice if things are all just jumbled together, unpriced, etc., so I make sure to arrange and price everything at my yard sales (OK, signs that say "paperbacks .25, hardcovers $1" not price each book individually); it's clear what things cost, stuff is laid out on tables, visible, clean, etc. It usually takes several days to prepare for a yard sale, and it's always a lot of work.
On my first yard sale of the summer, I made about $300, but I sold an old sofa, a gas dryer, five upholstered bar chairs, a dorm fridge, and four tires. Nobody was interested in the books, clothes, fabric, toys, shoes, etc. At the end of the summer we had another sale... made about $20, because all the bigger, "good" stuff went earlier! Both of these were neighborhood yard sales, with signs and ads in the paper (this was in the days before fb or cl!) For an average of $160, it was definitely NOT worth my time and effort. My opinion on yard sales is NEVER AGAIN!
The only "successful" yard sale we participated in was when DD's ballet company went to France. Eighteen families participated. We sorted, cleaned, and tagged every night after work, until midnight, for two solid weeks, with at least 5 families helping every night. It was a 2 day sale, and we made $2000. However, I think our real secret was our location: One of the dancers lived directly across the street from Stephen King, so that's where we held the sale! We had many, many cars and even a couple of busloads of people stopping to take pictures, and many of them then came to peruse the yard sale! The $2000 was nice, it was enough to pay costs for ONE dancer, and it was just so much work... and we still had to haul the majority of the stuff to Goodwill when it was all over.