Read the topic completely. Many students end up missing points because they answer only part of the question.
Make a brief outline of your essay or a list of key points. This will help you to be clear while writing the essay.
Write your opening paragraph. This should show both an understanding of the question and a clear thesis. You need to establish your position on the topic in this paragraph.
Create follow up paragraphs for your key points. When possible use a fact, quote or story to support your positions as much as possible.
Tie up all your points and restate your thesis in the conclusion.
If you have time go back and check your essay for content, clarity, spelling and grammar.