Look for careless errors, omitted answers, omitted words, and mismatched answers. You may find that information from later questions leads you to see an error in an earlier answer. If a question is confusing or just doesn't look right, ask the instructor. I have made typographical errors in exams or had duplicate questions. On multiple-choice questions, be sure to read the entire statement and all choices carefully before answering.
Single words can be crucial.
You are generally to choose the best answer, not the correct answer. Two answers may both be correct, to some extent, but one may be better. Only if you are unable to identify the best choice should you use the process of elimination. They may be distracters to catch the unwary. It can and often is.