Since you did not mention data insights, I assume you’re taking GMAT classic.
I would say that you can improve fairly well and steadily to about 80% but the last 20% of the hardest in any section. most people find sentence correction to be the easiest, fold by critical reasoning and everyone usually finds reading comprehension to be the hardest.
I would recommend that you get to 80% in all of the verbal question types. After that, you can focus on sentence correction and critical reasoning. If you find sentence correction extra difficult, you can always switch to the focus version. You will not have to deal with sentence correction but you will have to face data sights…
Posted from my mobile device