Yes study material is best for theoretical papers...because institute give numbers to those students only who right same language of material in paper..
Thorough understanding is required in the case of subjects like IT and SM. You better try understanding each and every concept. I suggest you to go for coaching. If any of your friends/seniors are doing MBA from a decent college, there are chances of having SM in their curriculum. In that case they can demystify the entire concepts along with examples. But even then, coaching still will remain as the best approach if you are willing to give ample amount of time for the other subjects.