Firstly, look at past papers. Knowing what has come up before helps a lot, and will be in the back of your mind as you revise, meaning you will begin to form arguments, and know what evidence you will include when given a certain type of question. I find that dividing your work by theme helps, e.g. religion, social, political and economical issues. This works as most questions given in the exam are divided by themes. After you have learned your timeline and events according to theme, you want to create your arguments and establish your opinions, so that you don't have to in the exam. Decide what you would say about the cause of a certain social movement, for example, and develop counter-arguments. But it is important to know what you are going to say, and will save a lot of panic in the exam! Lastly, create essay plans. Generic ones. Answer past questions. And you will soon know what points you would make if given a question on economics of a certain monarchy, for example, and what evidence you will use to support your answer. Then - you're ready for the exam!