There are two situations which arise for an aspirant when preparing for CLAT, getting into a law school is either the primary aim or it is not the primary aim.

Primary Aim

If someone wishes to 'clear' CLAT (assuming 'clear' here means getting into Tier-I schools) then she needs to focus on getting a good rank over the board marks. The simple reason rests on the assumption thatwhenyou get into a law school, the twelfth marks are pushed down on yourCurriculum Vitaeby the CGPA/GPA and get less preference in front of achievements like internships,publishing papers, moots, credit courses (specialization courses) etc.
This all sounds nice but it all depends on thedangerous assumptionthat the aspirant will get into a 'good law school'. So, the twelfth marks are not really considered in front of college achievements unless there is an awful fluctuation(it can either be positive or negative) during the placement.

Not a Primary Aim

Many aspirants are taking law as a backup and study other fields of human knowledge. Now the situation becomes complex and subjective because the intricacies involved in the preference of admission into a college may or may not depend on the twelfth marks. In this case, it is ultimately your call to make i.e. what do you want to do all your life which you will enjoy and believe me, law can be a good contender.