It doesn’t matter how long you use OSX, there is always something more to learn. Here are two little tricks that I came across recently, both of which you can use regularly. (These are both for Snow Leopard)
Speed up access to System Preferences
If you’re like me you access System Preferences most days, even if it’s something simple like adjusting the microphone input source there is always a two step process. One to open up the main windows and the next to get to where you want to be.
Well no more!
If you have System Preferences on your dock (and you should right?) then instead of clicking with our primary mouse button, right click if you have it, or control click to get the full list of what is available inside System Preferences.
Then you can navigate directly to the section you need.
I use Exposé a lot, but generally use the dedicated key on the Macbook Pro to bring up all windows that are currently open.
Here’s another dock based tip though, click and hold down on an open program like Mail for example and after about 1 second Exposé will show you all the open windows for just that program.