Exposé and Spaces tricks
Most people are aware of the different application and window switching tricks in OS X, but real power in tools like Exposé and Spaces is when you start combining them and using them together to really save time.
Firstly lets quickly go through the different ways to switch between applications and windows. The most basic way is to use the keyboard shortcut Command-Tab to cycle through your open applications, and Command-~ to cycle through the open windows of the current application. On top of this, you have the three different options for Exposé: Show all windows (F9), show current application windows (F10) and show desktop (F11). Your function keys may be different if you have one of the newer MacBooks, or if you have changed them in System Preferences. Finally, there is Spaces (F8), which allows you to switch between collections of applications and windows that you have organised into workspaces.
Using some of these techniques simultaneously is a great way to save time. My personal favourite is combining Exposé and Command-Tab. Start by invoking Exposé for current application windows (F10). Once all your windows are shown, you can hit Tab to make Exposé cycle through showing windows for each application individually.
If you are anything like me, when you have applications running in lots of Spaces you occasionally lose track of things. If you have completely lost a window, a great way to find it is to first invoke Spaces (F8) and then Exposé for all windows (F9). First, all of your spaces will appear, then Exposé will rearrange all the windows in every space so you can see them all. You can still drag windows between spaces, and as you do, other windows will automatically rearrange so you can still see them all. And as always with Exposé, hovering your cursor above one of the windows will give you its name.
The best way to find out what combination tricks work best for you is to just try hitting the different function keys in different situation. If you find any other great time-saving combinations, let us know in the comments.