Your introduction and even your first sentence are the most important part of your personal statement. This is where you can grab the attention of the admissions representative. Make your first sentence unique and compelling. It is recommended that you state in a creative way WHY you want to undertake this field of study in your first sentence. The rest of your introduction should provide a brief explanation that supports this first statement. Divide the word limit by the three parts of your personal statement by allocating your introduction around 30%.
The person you choose to look over your statement should be checking everything. Along with grammar and spelling errors they should check the tone of the paper, the flow of the paper, and the overall style of the paper. So, it makes sense that the person you choose to look over your admission essay should be well tuned in writing. Additionally, they should also be able to let you know if there is anything they feel you should omit or add. Once you have made the changes they recommend, then you should have them re_read your personal statement to ensure quality. If you want to be ultra_safe, then have yet another set of fresh eyeballs look over your revised personal statement.