Don't ask an obscure question. The goal is to reinforce the main subject. Figure out the most important point you are trying to make and use this point.
Write the questions as simply as possible and stay away from double negatives. The goal is to reinforce student's knowledge - not test their language skills.
When providing answers, provide extended explanations of why one multiple-choice selection is better than the other options. Make sure you alternate answers. For example, don't always choose answer b).
You can reinforce the point of the question by supplying an answer that not only gives the correct answer but explains why options were incorrect or why the answer was correct.