10. Use poor spelling or poor grammar _ This one should be pretty obvious. Academics on admissions committees are generally high achievers with high standards who won't disregard even simple typos. If your personal statement is not technically perfect, it can make you seem sloppy, lazy, or inattentive, which are not qualities anyone wants in a future colleague. Remember that the people skimming your essay are seeking a reason to reject your application and make the pile of possible admits smaller. Always get someone with strong writing skills to review your essay.
Once you have a good amount of information and several personal statement samples to reference you can then sit down and begin to put down your thoughts for your statement. Don't try to write your personal statement after only viewing one sample as this may inadvertently lead you to create a carbon copy of what you are looking at. By writing down your thoughts first you will be able to ensure that you are getting a good mix of ideas and inspirations from the various personal statement samples you like.