Step1
1. Densely populated city neighborhoods are your best bet for finding clothes in the trash. FoundClothing readers who live in suburban areas tell me that it's difficult to clothes-find in their neighborhoods due to suspicious (and sometimes gun-toting, violent) neighbors, locked-up trash cans and other obstacles. In my experience, the best city neighborhoods are either affluent or artsy-trendy; New York's East Village and Chicago's Lakeview neighborhoods are two examples of hot finding spots.
Step2
2. Start looking down. Sometimes you can find a dropped scarf or shirt right in the middle of the street. Make sure that nobody nearby is looking for the item -- you don't want to take something if the owner is likely to reclaim it. The magic word here is "abandoned."
Step3
Scope out dumpsters and overflowing trash cans. I don't consider myself to be a "dumpster-diver" -- in other words, I don't lift dumpster lids in search of goods, or root through people's trash. With the exception of the dumpster behind the Half-Price Books on the Drag in Austin, TX, I've never literally gotten into a dumpster. No, I simply glance. If I spot something that looks like a fabric object lying on top of a trash can, that's when I walk over and inspect. Sometimes I will check out an overflowing can whose contents catch my eye; this takes just a second. Of course, someone who has lots of free time could methodically open the lids of each commercial dumpster and look for clothing ... this might be a good hobby for retirees, actually.
Step4
When walking by trashcans and dumpsters, look for paper shopping bags. Often these contain clothing that conscientious people who don't want their clothing to end up in the landfill, but who don't have time to drop them off at a donation center, have set aside for the express purpose of attracting the curiosity of passersby. I have found collections of women's business suits and complete winter wardrobes folded and stuffed inside paper Ann Taylor and Anthropologie bags.
Step5
When you do find clothing in a trash can, be careful about how you pick it up. Don't just thrust your hand inside a trash can -- you don't know if there's broken glass, ickiness or another trap located within. Use just your index finger and thumb to make what I call "Tyrannosaurus pincers" and pick up the garment.
Step6
Bag it and smile! You've scored.
Step7
When you get home, turn the items upside-down and shake them. Don't stick your hand blindly into pockets -- there might be dark hidden secrets/total grossness in there. I've never had any bad experiences with pocket contents, but you just never know.
Step8
Wash your found clothes and wear them with pride. You've kept one useful item out of the waste stream. Your Depression-era relatives would be pleased.