In longer essays, you can end the introduction by briefly describing what will be covered in each part of the essay. This guides the reader through your structure and gives a preview of how your argument will develop.
However, it`s important to keep in mind that your professor understands the circumstances under which the essay was written. They`re fully aware of the time pressure you were dealing with, and they will judge your work far differently than they would judge a typical essay with a deadline set weeks after the assignment date.
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!
Unless if you finished way ahead of schedule, don`t worry about major revisions like reorganizing the structure of the essay–it`s better to hand in an essay with an imperfect structure than a paper that`s impossible to follow because you had to stop halfway through the revision process.
Although the conclusion paragraph comes at the end of your essay it should not be seen as an afterthought. As the final paragraph is represents your last chance to make your case and, as such, should follow an extremely rigid format.
If you have enough time left over, read your essay again and make corrections. When you`re working under time pressure, it`s easy to make grammar mistakes or produce hard-to-follow sentences; the final few minutes are your chance to clean up those errors.