I'm not always a fan of "verbing" words, but I am grateful for the word and the concept "calendaring". Calendaring is sitting with your calendar - whether it exists on paper, your smartphone, your tablet, or, as readers of Terry Pratchett might imagine, on a small box inhabited by an imp - and looking at how close its days and dates really are to one another.
Don't get caught scrambling to finish a paper, read an entire book, or cram for an important test at the last minute. Follow these three simple steps to become a calendaring pro.
Count the Days
When you've just had that big paper assigned, its due date is as far away and abstract as "next summer" or "the end of the known universe". Until you actually look at the calendar and count the number of days between that due date and today, the due date will remain abstract. As you're counting, take note of any special days. What do you (or does your family) have planned? Which days will be hard to count as "working" days because you have something else going on - whether the daily workload of school or an extracurricular?
Fill 'er Up
Now that you see where the busy times are, choose some available days and write in the name of the project. This is really important. You can't simply notice the space and plan to work on your project at that time; you have to make an appointment with yourself at that time. It's the weirdest thing, but writing it down not only prevents you from forgetting, it also makes the appointment feel official. When the designated time arrives, it will be a little bit harder to play your favorite game or alphabetize your socks without feeling guilty for standing yourself up.
Divide and Conquer
Now you have committed yourself to working on the project at specific times. But what will you need to accomplish in those sessions in order to complete the whole task? If it is a book you have to finish reading, bust out a calculator and determine how many pages you have to read at each "appointment" in order to get through the total number. If you have to read and write about the book, take the writing into your calculation - you can't expect you will read the last two chapters and write a thoughtful paper in the same night. If the project is writing related, think through the steps. Is there research involved? Will that require a trip to the library? Schedule a few note-taking sessions, an outlining session, a couple of drafting sessions, and one each revising and editing sessions. (This would be the ideal; you may have to modify.) Be realistic: taking notes and drafting each require a lot of time and energy and can't be done in one sitting. And don't forget, you want to be able to let your rough draft sit for a bit so that you can revise it with fresh eyes. That means your planned revising time should not be squished into a drafting session.
With a little practice, you will create a habit of writing down appointments and checking your calendar for what you have committed to doing. The long-term payoffs are huge. Whether you are writing a research paper or studying for an admissions test, you will maximize your preparation time. And besides, doesn't everyone want to be important enough to say, "Hold on, let me check my schedule"?