Consider Both Sides of Your Topic and Take a Position
Once you have selected a topic you feel strongly about, you should make a list of points for both sides of the argument and pick a side. One of your first objectives in your essay will be to present both sides of your issue with an assessment of each. Of course, you will conclude that one side (your side) is the best conclusion.
In the planning stage you will need to consider strong arguments for the "other" side. Then you'll shoot them down!