Giving Practice law exams means that you give mock tests....recreating the same environment and question papers as in the real exams and then solving them. In law...you must have realised that there is no perfect answer to a problem. The answers are given on the basis of prevailing laws...judgment of the constitutional courts...conventions and traditions which have the force of law.
Therefore I would advise you therefore answering a question you must ask yourself whether you know the latest law on this subject matter/issue and The judgment if any of the higher courts?
If the answer is yes then look for similarities in the judgment and the problem at hand.
Then try to write the answer justifying your answer with the help of the enacted law and the judgment but always keep in mind the facts and circumstances of the case at hand and those in the judgment.
You must realise that no two cases are similar and therein comes the lawyers' creativity....wherein he can justify the action/omission of his client and try to get relief.
The uncertainty of the law is the lawyers greatest strength.