It is not unknown for question-setters of the CAT to try and bewilder students with a large amount of data, most of it unnecessary. As a rule, the more the data presented, the easier the questions that follow, so don’t lose heart if you see a table with 10 columns occupying one whole page.
On the other hand, several seemingly innocuous questions may trip you up. Therefore, It is advised to look at the questions first to get an idea of what data you need to be searching for in the graphs/charts/tables in the main question asked.
Another interesting feature of DI that you as a student can use to your advantage is that, usually, not all questions in a set are of equal difficulty. Specifically, most sets have a ‘counting’ type of question
Most of these questions can be solved without calculation but by close inspection of the data presented. These I would categorize as ‘gift’ questions designed to test a student’s presence of mind, and should never be missed out on.
There is no rule that states that you need to attempt all questions in a set, so it is a perfectly valid strategy to attempt selected questions across your DI section, without perhaps completely attempting even a single set.