Highlight your accomplishments _ Some of your achievements may not fit into any categories on the application; talk about these accomplishments in the personal statement so they aren't left out. You could also use the personal statement to elaborate on an achievement that you are particularly proud of, but could not address in detail on another part of the app. Think of the personal statement as an opportunity to tell admissions officers anything you want them to know that wouldn't be perfectly clear otherwise. Don't be afraid to brag about yourself; your application is really all about selling a product__you__to the college.
Being an Apologist _ You do not use your personal statement to explain why you lack certain skills or experience. The point of writing this short paragraph is to sell yourself and this involves highlighting your strengths instead of apologizing for your weaknesses which in itself is a sign of weakness. The time and place for discussing flaws in your suitability is the interview and at that point, you must focus on how you plan to overcome any holes in experience/skills etc.