Consider practicing writing under time pressure. You`ve probably written dozens of essays before–the only thing that sets a timed essay apart is that it`s timed. Students often struggle to complete the full essay within the time constraints, particularly if they have to write longhand when they`re accustomed to working on the computer.
For example, if you`ve been assigned a five-paragraph expository essay for a high school class, you`ll probably spend the most time on the writing stage; for a college-level argumentative essay, on the other hand, you`ll need to spend more time researching your topic and developing an original argument before you start writing.
Some students react to the time pressure of essay exams by scribbling down their introduction as soon as they`ve read the question and figuring out their points as they go. While it might seem counter-intuitive, taking five or ten minutes before you start writing in order to draw up a plan will be an enormous time saver.
Decide on your thesis, the topic of each paragraph, and the arguments which you intend to cover, then jot down some quick point-form notes. This process won`t take long, and, once you complete it, all that`s left will be to expand those notes into a well-organized essay.
For this reason, it can be helpful to simulate the conditions of a timed exam before the actual day: pick a practice question, find some lined paper, set a stopwatch, and see how you do!
Without a clear plan, you run the risk of realizing partway through that you`ve drifted off topic or written yourself into a corner, and fixing these mistakes will consume a ton of extra time.