The body of your personal statement is going to be hard work _ you need to use around 50% of your word limit to give the admission representatives concrete evidence of why you stand out from the crowd in this application process. The body is also where you will be answering questions and giving examples of experience and affects of experience. Answers and evidence need to keep reflecting who YOU really are. If you're struggling to keep under the word limit, allocate each question a word limit as well.
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.