Then look at some resources for writing personal statements and get some advice. There are lots of websites which will offer you advice for writing a personal statement but it is best to look at websites from reputable organisations such as UCAS or student advice websites which are well used such as The Student Room. Remember to ask your teachers, friends and family for advice. A good question to ask them is "what do you think makes me different from other people? or "how would you describe me?" because the answers often give you some interesting information that you hadn't thought about. The personal statement is not something you can write quickly so be prepared to think a lot about yourself, your qualities, skills, experience, likes and dislikes. You are unlikely to meet the people who read it so your personality needs to come though on paper; this is difficult.
When you are sifting through the vast amount of sample you will have access to, be sure that you are looking for samples that will pertain to you and your personal situation. Once you find sample personal statements that you think have helpful information you can print them out and highlight any areas that you feel may help you when you set out to write your own statement. It is also a good idea to take notes as you go along.