I guess everybody uses their own method. I had a booth at the flea market last year, and it was okay, but I did not feel like it was worth my time. My best and most consistent outlet is craigslist, followed by a couple of thrift stores I sell directly to (I don't generally consign). Then lot's of stuff goes to individual buyers that take certain items (baseball cards, jewelry, lawnmowers, books, etc). Lot's of stuff goes to the local auction house (I've found that the "shows" have also affected the local auction houses. Shows like "Auction Kings" has everybody heading there too, so if you are looking for a deal, it's not the best place to go, but if you are selling stuff, you generally are getting top dollar right now). Some stuff still goes on eBay, although that is one of my last resorts now........they have given all the power over to the buyers and they don't want the small guy there anyway. Then, there are also the garage/estate sales. I've had some good ones, but lately I have been doing so well with my thrift shops and everything else that I'm not letting all the stuff build up for a good sale, so I probably won't be doing as many of those as I used to.
Oh yeah, and TreasureHawk, keep in mind that while the "home runs" are harder to get, there's a lot of money to be made on the "bread and butter" units that a lot of guys overlook. High quality stuff can be hard to find. Also, a lot of the high quality stuff can be hidden. I've had more than one unit I thought was going to turn out to be garbage, but once I dug into it, there was a lot of good stuff in the back. I just had one recently where they made a little cubby hole in the back of the unit. They had two sofas set up on end and a TV and stand blocking everything else. I ended up with a really nice Queen bedroom set with a sleigh bed, matching dresser with mirror, and a night stand. Also had a washer and dryer and a lawnmower hidden back there. Ended up doing really well on that one, but it did not look that good from the front (I bought it because I was pretty sure something was back there, most of these people wouldn't set there stuff up like that unless they were trying to hide something).