Compartmentalize your desktop to a single task per screen.
Quick Tip: Eliminate Distractions On Your Computer
Your computer can be a huge distraction. Eliminate your computer distractions! Don't open all your applications at once; only open the application you're working on, and complete a task before you open any unrelated program. This includes browser tabs! Close all browser tabs unrelated to the task at hand. You can also use a "virtual desktop" program like VirtuaWin or Mac OS X's built-in "Spaces" (choose System Preferences | Expose & Spaces) to create virtual screens. On each screen, have only the windows related to a single task.
(Stop! Look at your screen right now. How many distractions are visible? How many different applications, documents, and projects are fighting for your attention?)
To set up your own virtual desktop head to http://virtuawin.sourceforge.net.
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