The skills required to crack questions to crack the he Common Admission Test's (CAT) Data Interpretation & Logical Reasoning  (DLRI) are..

Ability to analyse and understand difficult/complicated data
This is a skill acquired through regular practice. The practice needs to involve questions of various difficulty levels and types. One approach would be to start solving all the DI & LR sets from your study material. Once this is done, it is time to move online to use online
practice tests.

Ability to do calculations quickly
Speed of calculations is what the students should focus on, along with practising different sets. Acquiring this skill is often easier said than done
as it is difficult to get over the old habits of scribbling numbers on a paper even for simple additions.

Topics on the hit list

Caselets Puzzles: Distribution, selections, comparisons
Reasoning-based DI Puzzles: Seating arrangements
Games/tournaments: Quant-based reasoning
Maxima and minima Venn diagrams
Tables, networks Cubes & binary logic
Line/bar/scatter graphs/pie charts