My wife has always marveled at how well we usually do with these sales, wherein one gathers up unused or unnecessary items, making them available for sale. We've had probably a half dozen over the years, and exception we sell most everything that we intend to sell. The trick we've found is to determine what you're willing to get rid of, attempt to sell it, then take what's left to a charitable organization (like Goodwill, the Salvation Army or the like). That way, once you've made the conscious determination to part with an item, it goes away, so you're more ready to sell!
Here's a great example: last time out, I went though our books and DVDs, culling those titles that either didn't interest us anymore or that we simply didn't like (and that happens, believe me). Put those out for the sale, despite my wife's comment that no one was going to buy them, and wound up selling them all. Certainly, we didn't get top dollar for them, but they went away, and I had enough cash in the exchange to buy lunch.
And the funniest thing is that you cannot tell who's going to buy what. When I prepped for my last sale, I had accumulated a number of the giveaway bobblehead dolls from my beloved Cincinnati Reds. They're cheaply made, rarely look anything like the actual player, and take up space and are hard to clean around. So out they went. Can you believe that I sold them all to a seventy-something granny, buying them in hopes of surprising a grandson?
I like it when flea marketers come to call. Once I sold a twenty-year-old ladder, spattered with paint and rusting at the hinges, when a flea market dealer came and literally cleaned me out the first hour I was open. It was a throw-in, but I got ten extra bucks I didn't expect.
The garage sale concept can be extended to Craigslist. I know, one must be careful using that venue for buying and selling, but as long as you deal only in merchandise and accept cash only, all should be well. So far I've used Craigslist to sell old exercise equipment, an old cellphone (yes, it's possible), and most notably my old pipe collection. Since I hadn't used it since suffering a heart attack in 1993, and since doctors are never going to say that smoking in any form is harmless, it was time. And I had three different collectors vying for the opportunity to buy my collection.
Right now I'm in the midst of selling a couple more items on Craigslist. It astounds me that people are apparently shopping regularly and actively on that site, as I had an inquiry about an electronics item within an hour of posting it. At 9:00 this morning!