G. Mark’s Answer
First thing you should do it put an outline together. And how to do that if you've never written a statement of purpose before? You research the task just as you would any other task. And with the internet, you have vast amounts of info available, so look around for other statements of purpose examples. Then you look these over and see what the commonality of the best ones is. Categorize each section into a heading -- for example, "overall purpose", "My eventual goal," "What I want out of a career," and so on. These general headings are your outline and give you your organization. This will give you the kick to get started on each section because you'll already be focused on the subsection content when you begin writing. A further help is taking these sections to as many other people as you can. Get their reaction. Hear their questions. Hear their criticisms. So instead of just winging this on your own, take advantage of all these resources. And you'll end up with an organized and focused version of exactly what's in your heart and your head and you'll be more confident of its being able to convey that to your chosen graduate school. When I've got a task to do, especially one I haven't tackled before, I don't like to take chances. I want to see what my target audience expects and wants first. So do that. Sound good? Takes a lot of the anxiety away, I think.