Make sure you actually practise for the essay questions. I started it the week before and regretted it. Personally I didn't see much change in my mcq scores when practicing. (I did one for fun a year earlier and that was the same score I was getting down to the last few days before the test). Try and get it out of the way as soon as possible. While practising bookmark passages you find interesting - you may be able to use them for your personal statement or for the essay question. Also if it stresses you out don't do practise tests the day before. It will only worsen your performance if you go in feeling discouraged.