What are the pre-requisite to start solving Data Interpretation section .

percentages and averages prepare these chapters well and then solve

percentages , averages  and ratios your entire di charts will be based on your command on these 3 topics only

First major pre-requisite is you should be good in calculations. You should be able to multiply 3 digit numbers in 10-15 sec.

Be good in multiplication tables (preferably upto 20 or 25).

You should be very familiar with reading and understanding all types of graphs(bar, line, pie chart, etc)

If your calculation speeds are fast then you can easily solve DI within a reasonable time limit.

If you find any question which requires a lot of calculations and comparisons(Especially questions that ask for data like the highest score or least score), it would be safe to skip these. Maybe you will be able to solve 2qs in a different topic rather than one difficult question in DI