Hi RashedVai,
In simple terms, a CR inference question is essentially the same thing as an RC inference question. That having been said, since an RC prompt is typically longer than a CR prompt, you might end up having to read more information to properly determine an inference in an RC passage - and the overall note-taking process for RC is different from the note-taking process for CR. Thankfully, the Verbal section of the GMAT is just as consistent and predictable as the Quant section is, so you CAN train to score at a higher level in Verbal.
Since your question is Verbal-focused, I assume that you're most interested in improving in the Verbal section. Before I can offer you any additional advice for your studies, it would help if you could provide a bit more information on how you've been studying and your goals:
Studies:
1) How long have you studied?
2) What study materials have you used so far?
3) How have you scored on EACH of your CATs/mocks (including the Quant and Verbal Scaled Scores for EACH)?
Goals:
4) What is your goal score?
5) When are you planning to take the GMAT?
6) When are you planning to apply to Business School?
7) What Schools are you planning to apply to?
GMAT assassins aren't born, they're made,
Rich