How should I prepare for DILR?

1. Get a copy of the syllabus first , i mean all the main and important set types .
2. Watch YT playlist of ElitesGrid and Cracku for them.
3. Solve Sudoku daily to improve problem solving ability
4. Practise all PYQ'S from 2017
5. Before CAT exam , you should've solved around 300-400 sets
6. Don't jump on the solutions unless you have spent around 15 minutes on a set initially, check for where do you actually go wrong and then revise those sets regularly

the same thing happens with me too, the only thing that my mentors tell me is to understand where you went wrong, write it down on your error log book. not the solution but the reason why you thought , and what was the actual thought process, i know its boring, but it helps when you write these things down.
and obviously, practice more