One of OS X’s nicer features is Smart Folders, which are basically saved searches that act as folders. Too many can clutter up your sidebar, but here’s how to create Smart Folders that only show up for specific applications.
Sharon Zardetto, over at MacWorld, offers up a bunch of tips for working with smart folders in Mac OS X. One of the most interesting is how to make application-specific smart folders. It’s actually really simple: when you’re in the open or save dialogue of an application, just conduct a search, and press the save button. When you save this search, it will only show up in the sidebar of that application, in the Saved Searches section. This is really useful if you have tons of documents for a particular application but you only want to see 1) the documents created in that application, and 2) documents that were created in the last seven days. You can do this and a whole bunch of other neat application-specific stuff with this trick.