I keep running out of time in the exam, what should I do?

It's really easy to do in history; you have so much to say and so little time in which to say it. Organisation is key here, both in your revision and your exam method. It is worth identifying the key events in your period of study when you revise, so that you can see where changes have come from and why, before you start to add in more nuance and flair to your arguments. That way, in the exam, you can ask yourself which of those events are relevant to the question and prioritise them; this can be a great starting point when planning your essay. On that note, it is a false economy not to at least briefly outline the plan of your essay. Waffling and overly ponderous paragraphs are usually a product of a lack of clear direction in your writing. Always plan. Remember that you can't include everything: if it is irrelevant or it doesn't help your argument, it doesn't belong in your essay. Practice doing essay questions both individually and as part of complete practice papers. You'll get a sense of how much it is feasible for you to write in the time allotted to that particular question; try to practice sticking to that time and amount. Finally, it might be advisable (depending on your style of working through exams) to answer the questions that are worth the most marks first to avoid dropping too many marks if you do run out of time.