Lion’s Mission Control combines features from Snow Leopard’s Spaces and Exposé, but makes them more usable. Here two tips that make Mission Control easier to work with.
First, to help you distinguish virtual desktops from one another, specify a different desktop picture for each one. Launch System Preferences in your first desktop and choose Desktop & Screen Saver. Set the background image you’d like. Then enter Mission Control (by pressing Control-Up Arrow, using the three- or four-finger up-swipe, or clicking on the icon in your Dock).
There, drag the System Preferences window from its current workspace to another. (If you haven’t yet created a second desktop, drag System Preferences to the upper right corner of the screen when you begin the drag.) In the Desktop & Screen Saver pane, choose another desktop picture; it will appear on that second desktop only. Repeat this for your other workspaces. The different backgrounds will be saved after you restart.
Second is an efficient way to switch desktops without exiting Mission Control. Say you’re in Desktop A and you want to drag an app to it from Desktop B. Clicking on Desktop B would cause you to exit Mission Control and go to Desktop B. To avoid that, hold down the Option key when you click on Desktop B; that will open it within Mission Control.
To make it easier to distinguish Mission Control workspaces, give each one a different background