Whilst in a lot of subjects your essays will probably be explorative and balanced, inn Law you want to make your essays a clear argument. Start by giving your response to the question or phrase given then briefly going through the points you're going to raise throughout the essay to support this. You'll want 3-4 well developed points with responses to counter arguments where necessary. Finally, your conclusion should wrap everything together- not bring in new points. Don't over complicate the structure, the best essays are clear and answer the question raised. The structure will not matter unless the content you're writing is relevant to the question.