There’s an art to turning your trash into someone else’s treasure. But it’s easy once you know the tricks. First up: a hunt for merchandise. Move obvious sale items into the garage (or another staging area) and do a clean sweep of the attic and basement. Then go room to room, box in hand, checking cupboards, closets, dressers, and storage bins for stuff you want to off-load.If you're not quite sure what will sell, follow these guidelines.