The first thing that you need to remember is that you want to avoid creating a generic personal statement at all costs. If you are applying to several different schools, you might want to cut down on the work that you are doing, but this can be like shooting yourself in the foot. An admissions committee will be able to recognize a canned personal statement quite easily, and unless you take steps to individualize it, you are going to get dropped a few spaces. Remember that every personal statement should relate to the school that you are considering. Research what the school's ideals and purposes are. This should be reflected in your personal statement and how it makes you a good fit for them.
Another thing that you need to consider is how well you know their formatting. Depending on the prestige of the school that you are applying to, you may be looking at a place where they need something really detail oriented. As such your format and construction could be disqualifying factors. Following the directions is the easiest part of the process, so don't get it wrong. Make sure that you use the format that they are looking for, that you adhere to their word limit and that you answer the questions that they want answered. This is essential if you want to move forward. Don't let something silly like the format hold you back!
Also, remember that your personal statement should be the sum effort of several people. This does not mean that you should let other people write your essay! As a matter of fact, you need to write your personal statement out in advance, and then hand it over to a trusted friend or advisor. They can tell you about how things read, whether you contradict yourself, and other things that you need to remember. The more people you have working on your personal statement, the better. This is extremely important when you are thinking about getting the results that you want and you never know when someone is going to have some important insight into your work.
What are you doing to make sure that you are going to be getting the right kind of result from your graduate school personal statement? This can be the deciding factor regarding where you get to go to school, so don't dismiss it!