At the outset, we congratulate you for having a set a goal for yourself of an MBA!
If you are setting your focus on taking GMAT as an exam-here are the few pointers:

(i)Decide when you intend to take the exam based on your career and life objectives.

(ii)Once decided, have the syllabus ready at hand.

(iii)Jot down your weak and strong areas and start by getting STRONGER at your STRONG areas to fetch scoring marks from these areas.

(iv)Once that is done shift your focus to complete the other areas and complete your course.

(v)Make sure your basic/fundamental concepts find a firm root in your understanding!

(vi)Practice questions from the chapters that you complete.

(vii)Give enough mock tests, analyze your scores and mistakes and make sure you keep taking those tests.

(viii)Complete the Official Guide questions.

(ix)Revise, revise and revise-there is no possibility to skip this!!!

(x)Stay connected with your mentors and ask them your questions,doubts,concepts or anything that you need assistancein. Remember,no doubt or "query" is insignificant. Just ask!

(xi)Now, to make sure the ten points find a meaning and are streamlined- MAKE a SCHEDULE according to your time availability and make sure you STICK to it!

Summarizing this - Plan + Decide + Schedule +Fundamental/Basics + Practice + Official Guide + Mock test + Revision + Daily Work+Positive Attitude is all that is needed to have a good score for the paper!!
We wish you all the best and cant wait to see you in apremium B-school!

All the Best !