The very first step to begin with is to read all the questions thoroughly to see if there are overlaps or similarities in the questions. Understand the questions and just focus on it. Once you are done with it, the next step is to brain storm the ideas. Reflect your thoughts and make a mind map out of it. Collect the points which come in your mind. It will eventually help you to compile a productive statement later. You can brain storm about your personal background; development of your interest in the field you applying for; your specific experiences that helped you explore and identify your career interest; any unique, distinctive, and/or impressive about you or your life story; about any work you did as an intern; your career goals; any special research, academic work, employment, volunteers experience, which you have performed so far; your strengths and weaknesses; any obstacles, which you encountered in your life; any unique skills that demonstrate the depth of your experience in the field, etc. All these refection will give you a rough data, which could be used to begin with your personal statement After collecting points, begin your formal statement. Do not give any heading to your statement. Keep in mind not to write in the third person and do not use the passive voice. Concentrate on your opening paragraph. This paragraph becomes the framework for the rest of the statement. It either grabs the reader's attention or loses it. Don't write more than 3λ lines in your initial paragraph. Give your brief introduction and then turn towards the main questions. Use short sentences and avoid long ones. Don't discuss extra things in the opening. You can keep that aside for including in the following paragraphs.
The personal statement is also a great place to explain more serious problems, like less_than_ideal grades or test scores. Don't be afraid to write something like, "I don't test well" in the statement. As long as you can provide a good reason for you app's problems, it's okay to address them directly. You won't be able to hide it from admissions officers anyway, so providing a reason for problems is always preferable to ignoring them.