You keep your files organized into folders in a way that makes sense to you. Accessing these folders can sometimes be less then convenient when you have lots of applications and folders open on your screen. Here a three shortcuts that'll let you quickly open folders you commonly access with a single click (or two).
In Mac OS X, when you open a new folder window, you'll see a sidebar at the left of the window that displays three lists (sometimes four), "Devices", "Places" and "Search For". (And, if you're on a shared networks, a "Shared" list.)
You can add your favorite folders to the Places list. Just drag the folder into the list. Now, when you want to quickly get to that folder, open a new Finder window (or, find one that's already open) and click the folder in the Places list.
Mac OS X Dock
You can drag a folder into the right portion of the Dock. Because you have access to the Dock anytime, no matter what application you're in, you can click to open the folder instantly.
Recent Folders Menu
While not as convenient, you can open a folder you've recently opened. Click on the Desktop. Then, select a folder from the Recent Folders list in the Go menu.
As you can see in the snapshot, the Go menu also gives you a shortcut to many other common folders in Mac OS X, such as your Home, iDisk, Applications and Utilities folders.