When you have finished question 1, go on to question 2 and forget everything else including question 1. Read the questions naturally but carefully, just as you would read the textbook, or hear the lectures. The teacher puts a lot of care into wording the questions in the most natural, direct, easily-understood, and clear way. But scientific writing is not like street-corner conversation. The specifics, the details, are important.
Most questions are about ideas, rather than about simple facts.
Don't return to old questions. Once you've decided on an answer, your decision should be final. Any rethinking is likely to be superficial and wrong. If you must return to an answered question, spend twice as long on it as you did the first time. Return only to those that you couldn't answer the first time.