With mock exams looming now is the time to start preparing for them. There is no better way than to practice as many past papers as possible so as you get a feel for the exam style questions. It is important that you know what exam board is issuing the paper as well as the syllabus code and the level at which you are studying at, e.g Higher and Foundation.
Remember the better prepared you are the more likely you are to obtain higher grades. Simply reading through a text book is not adequate preparation. The more questions that you can do the better!
Past exam papers are available directly from exam board websites, also they are available from the Top Maths DVD website where you can download them free of charge.