We love to do garage sales. Unfortunately, they're hard work for very little return on your time.
We prefer to have things sorted by type & to hang as many clothing items as possible. We feel it's easier for customers to flip thru hanging clothes than digging in piles on tables or the ground. Besides, I HATE to dig when I go to a sale. A tip we discovered while going to sales was to drape ropes over the rafters in the garage & hang a pole between. Perfect clothes rod! Then we separate into girls/ladies/boys/mens clothing & if we have the time, we'll even separate each section by size.
DD even puts toys in plastic bags so parts stay together & kids shopping with their moms don't play with them.
At our local home repair store (like home depot/mennards) we purchased saw horses & plywood boards to use as tables. We store the boards on their sides by a wall in the & the sawhorses flatten so they don't take up that much space.
We save plastic grocery bags for our sale & a week or 2 ahead of time, we start putting aside change so we don't have to go to the bank.
Lots of work, but fun too, especially if you can get a few neighbors in on it. The more the merrier.
When your sale is over, everything's ready for SVP or GW to pick it up & haul it away. They're picky now though; they wouldn't take my typewriter with stand one year. Made me happy because I wasn't wanting to get rid of it!
So the gist of this post is to have a sale & donate when it's over! Have fun!