1. Write in simple English. 2. Be genuine. 3. Be specific about your academic interests, achievements and goals. 4. Think about life and how you wish to live it, and then write honestly about your hopes, fears and aspirations. 5. Think about the communities to which you belong and write honestly about your aspirations for them.

Start early and have a few different native english speaker proof read it. Learn from the process and it will still be genuine. A graduate school knows that applicants have their papers edited, and even encourage it. I do not agree with the previous poster-- yes, you should show your true self but a graduate committee would immediately disregard a personal statement that was not edited. They know that there is a lot of help available for students, and they would see it as a weakness that you did not put in the effort to find that help. If they want to see your true capabilities in english language they will look at GRE/GMAT scores or other tests that examine english proficiency. Good luck to you!