Focus on What You Can Do Next
Anyone getting back a bad test is liable to be upset. If it happens to you, resist the temptation to blame a sadistic professor or noisy roommates, or to throw out the exam and do nothing at all.
Take a few days off. Once you can look at your results a little more dispassionately, be honest with yourself. Did you devote too little time to studying beforehand? Were you tested on material which you only skimmed, or didn't fully understand? If the answer to such questions is yes, plan to correct your study habits accordingly.
Understand What Your Exam Mark Means
In the meantime, put your exam grade into context. Instructors often tell their students what the average marks were; if yours doesn't, feel free to ask. If you got a B- and the average was a C, you may not be doing as poorly as you think.
Also consider how much your first test is worth as a percentage of the course. Most classes put the most emphasis on the final, so you will still have enough room to improve by one or two letter grades.
Review Previous Tests and Essays
The best way to prepare for your next essay exam is to analyze your previous one. If it was divided into different sections, were there some which you did better on? You may have written a good essay, but unsatisfactory answers to identification questions may have dragged down your grade.
It's very important to read any comments your instructor has written in the margins, especially on essay sections. They will help you understand the specific concerns about structure, interpretation, or argumentation he or she may have had with your work. Ask for clarification if you're not sure about the reasoning behind the grade.
Comments on a term paper in the same course can provide extra insight as well. The principles of formal essays and essays written under examination conditions are the same, even though the standards (such as citing sources) are different.
Utilize Campus Resources
Seek outside help if you still can't figure out where you went wrong. Talk to the person who marked your test, whether it's the professor or a graduate teaching assistant. Don't argue about the grade (unless there was a mistake in adding up marks, for instance), but focus on asking what you can do to improve.
Another option is to find a learning skills counselor, or similar support staff member. Many universities and colleges have drop-in centers or department-specific writing clinics where you can get extra assistance. Of course, if you've already followed the steps outlined above, you'll be able to get the most out of any second opinion.