Unlike other forms of essays, persuasive essay needs to have a strong hypothesis. The reason for this is that it sets the entire tone of what is to follow. If you do not have a strong afford it is sounding a hypothesis or argument, then you may find it difficult to remain on track as you go through your writing. In short, any title that poses the question opens the door for reader doubt and is not something that you want to use. You also want to take a look at the use of your language within your title as well. Is it strong and does it have an air of authority, or, does it sound unique?
With regards to the body of your work, remember that you are arguing a particular position and as such you need to make sure that you don't go off on a tangent and start looking at the topic from both your position and the opposing one. That being said, you can bring of opposing find points of view if only to use them instead of having your own arguments or to refute them. Remember the idea here is to sway the reader to your point of view and you can't do that if it sounds like you're arguing both sides. You also want to make sure that your thoughts remain coherent from paragraph to paragraph.
Of course, the key point to writing persuasive essays is a strong conclusion. He in it, you want to restate your position as well as restate your proof as well as any points that you think are salient.