The best way to conclude an essay is to ensure that you relate back to your earlier judgements that you have made in earlier paragraphs, briefly explaining why you have come to the conclusion that you have. Even if you believe that one of the points you have made is insignificant in comparison to other factors, you have to briefly explain why you believe this is the case. It is important to make sure that your final conclusion is balanced, accepting why alternative conclusions are valid, but you also need to make sure that this doesn't prevent you from clearly stating and justifying your own view. Finally, you need to leave enough time in an exam to write a substantial conclusion to bring your essay together, but it does not need to include minor details as you will not have time in the exam, and the intention of a conclusion is to justify your viewpoint, not to add any additional information.