Kevin's method also works. Really, when it comes to getting started on an essay, you need to find a technique that works for you. Some people need to come up with an outline. If they just start writing, their ideas go all over the place and they end up being even more confused than before. Or, they just aren't prepared to delete anything they've written, so they keep in material that should have been cut early in the revision process. Other people find it much easier to write the outline last, if it has to be written at all. They come to their ideas through the act of writing itself, and so naturally find it impossible to write an outline of their ideas before they have actually written anything. Be careful, though, when experienced writers tell you that they never bother with an outline. They may think they are telling the truth, but often they are being deceptive. For instance, I never write an outline before I begin work on an essay. However, this is true only in a literal sense. That is, I don't type an outline out in Word. I do organize my thoughts logically in my mind, though, so I am working to a plan. In that sense, I have an outline, it is just that it is a purely mental one. Writing it down would be annoying for me because I can get further faster by just starting on my ideas and cutting and pasting them as I see the need to modify the plan I had in mind.
All that said, if you are really worried about the essay and can't get started, just freewrite. Get something down that destroys the horrible blankness of an empty page or screen. That endless field of white space can be paralyzing, but it is like paralysis in a dream -- it never breaks so that you can move, so much as it breaks just as soon as you start moving.
Sean, EssayForum.com