What you do in the last month is determined by what you have done in the previous months. If you have worked through the course notes then revise a section, for example corporation tax, and then from an exam / revision kit work through the past exam questions. This process should then be repeated for other areas, income tax, CGT, VAT, IHT. These questions should be worked under exam conditions within the available time and to exam standard presentation. Clearly each area must firstly have been studied and course notes examples worked to allow a realistic attempt at the exam standard questions!