Hi
varshaaaaa,
No experts have replied to this so I will provide my 2 cents based on my experience prepping for GMAT and the DI section.
First off it's recommended to start prepping for DI only AFTER you are done with your quant and verbal prep because almost all the DI questions test you on very similar analytical, critical thinking, and problem-solving skills further combined with graphical interpretation and tabular data analysis skills.
I will further advise that to make sure that you are starting DI prep with a solid foundation targeting 655+, begin DI only once you are achieving at least 65%-70% accuracy consistently in Hard question sets in both CR and RC. Otherwise, you'll trip on the same types of mistakes in both the verbal section and the DI section because of lacking fundamental critical and analytical skills. Not to mention that problem-solving skills are also important which is honed in quant section prep. Try to achieve similar levels of accuracy for PS questions before beginning DI to avoid calculation errors etc. in those problems.
Once you reach the above milestone 70% part of the journey is done, and after that, it is only about getting used to the different DI question patterns and gaining familiarity across question types. I will advise you to prepare DI section-wise, that's how I did it. A couple of benefits according to me for section-wise prep compared to solving RNG problems are:
1. Easy/convenient to identify mistakes in a particular section and do course correction in the question attempt strategy. You can quickly observe in the sectional tests whether the new strategy is helping improve your accuracy.
2. Solving several questions of a single type in a streak will help you get used to those problem types quicker and identify the underlying skills tested in those problems.
I recommend preparing for the question types in the order GI, TA, TPA, MSR, and DS. The reason for this order is that GI and TA are similar based on the given data types (graphs and tables). TPA and MSR are often very wordy with lots of reading - MSR is especially very wordy at times. There will be a lot of clutter in these questions but you'll have to see through that to find the useful information and operate upon it to arrive at the correct answer.
You can use the above points to make an informed decision on your approach and tailor a plan that works for you

Cheers!