The Personal Statement
The personal statement is your chance to say anything about yourself which you feel is important. It is your opportunity to describe your experiences and goals and to present yourself as the best possible candidate for a given medical school. You must write a general personal statement for the AMCAS application, and you will most likely have to write more specific statements for each of the schools to which you apply.
Do not simply use the same personal statement for all. While it is fine to demonstrate your general interest in medicine on the AMCAS statement, you should use each institutional statement to describe why you are suited to that particular school. For example, if the school is recognized for training the best cardiologists, you should express why you are interested in that field. However, be careful not to express a false interest: this would be discovered in the interview. In this example, if you were not interested in cardiology you should perhaps apply to a different school or explain why you are qualified despite your lack of interest.
Perhaps the best advice regarding the personal statement is to start writing it early and to revise it frequently. Before you start writing, define and outline your personal goals. This will give you a direction and will help with the flow. Use the opening statement to capture the attention of your audience, and avoid cliches such as, "I want to be a doctor because...." Remember, most admissions committees read hundreds of statements. You want yours to stand out. Avoid abstract words and concepts. Be specific and concrete when describing experiences and goals.
Be careful about explaining away the negative aspects of your application. If you had a year of bad grades, wait for the subject to come up in the interview and deal with it at that time. The statement is a place to sell yourself, not a place to offer answers to questions that may or may not exist. If you are not hung up because of one year of bad grades, and can demonstrate that to the committee, it will speak volumes about your maturity level. If you must explain deficiencies in your application, do not dwell on the subject and do not offer excuses. Deal with the question quickly and firmly, and move on.