Of course you are the ideal student. You have been studying for weeks: reading and rereading the material, meeting with your professor to work out difficult concepts, and examining countless outside texts to get ever more information on your subject. Lately, you have even devoted more time to writing sample essays than text messages.
You have gone beyond the call of duty for any student. If college tests were more like high school sports, you'd be going to state.
However well you prepare for an essay test, you may still have trouble once the question rests in front of you on that menacing exam page. Here are some practical tips from the reigning state champs (three years running!):
Read over the whole test.
If the test incorporates a mix of questions (multiple choice, short answer, essay, et cetera), identify the section most likely to give you trouble. Jot down short notes for difficult questions, and skim past the questions you know by heart and can return to with confidence at a later time. Recently learned information (i.e. cram-knowledge) has a tendency to flee your brain come test time, and it would behoove you to make sure your caffeine-fueled, last minute work was not for naught.
Students often focus too much on one section without leaving enough time to answer other sections adequately. Giving yourself general time limits for each section ensures you answer each section to the best of your ability. If you finish one section early, you can return to another you left incomplete or work on revising your answers.
HOW TO WIN THE GAME
Get your ideas down on paper.
Perhaps you draw a blank when facing a blank page. In this case, you may want to pick out the points in the question you want to respond to and write those down. Then you can begin to outline what you know based upon what you want to say. Some people prefer to begin writing right away, but if you do this make sure you have a general outline in your head. Otherwise, people have a tendency to trail away from the direct response to the question. Instead of sticking to the topic of, say, writing essays, a writer may get off on a tangent about high school sports.
Buy time by the line.
If you have forty seven hours to complete an essay, you can afford to stray a bit from the answer in favor of style. In a timed test situation, you probably would be better served getting to the point and supporting it to the best of your ability. Avoid redundancy and filler language; this stuff may help you reach ten pages but it will not help the professor understand your point. Many professors prefer a concise, accurate answer to a rambling epic.
Going to state with A-answers!
A professor once shared some test-taking wisdom with me regarding short answers: "I want you to tell me what it is, but also tell me something interesting about it." He meant that a B-answer gives the facts; it may even provide good support for the claims. An A-answer goes a step beyond. In the case above, I was taking a political science course. Going in-depth meant tying the facts to real world situations. An A-answer for a literature test may imply providing an analysis comparing the facts in the work to larger theoretical issues or perhaps other works.
In brief, you may do well to draw connections between the basic facts and either real-world events, theoretical approaches, or similar instances be they in the realm of the sciences, business, or the liberal arts. Try to manage your time appropriately, and record what you know on paper. Even if you don't have a chance to incorporate the material, your professor may credit you for your breadth of understanding.
If all else fails, you could always emulate the ideal student, but I think these tips may be more realistically helpful advice.