See MBA colleges are many and henceforth to get into a good mba college have many routes but you will have to be more specific about what stream or what college you want to join and then accordingly target the college. As the variety is huge options are also many and henceforth you need to be pretty clear about what you are aiming for. 

There are many top institutes and each of them accepts a different entrance exam score and accordingly the further procedure will take place. 

For example: IIM’s specifically accept Cat score as their main entrance criteria but their are many different exams conducted across country which are accepted by many top colleges like XAT is accept by XLRI which is considered one of the best college for HR and then comes TISS for Tata institute for social studies again a excellent college for HR then there is NMAT, MH CET, MAT, ATMA, CMAT, etc and many colleges specifically ask for any one or two of the given exams and thats why clarity of college and stream in MBA is necessary.

To get into a good college is IIMs, FMS, SP JAIN, MDI, etc you have to first prepare for and give CAT exam. The preparation strategy will be as follows:
Now you have 7 months now for preparing for cat.
For verbal: start reading newspaper daily and pick up books to boost your vocab. Increase your reading speed.
For di/lr: this section is always the toughest in cat referring to previous years pattern. start with bar, pie, bubble, multiple chart sums. For logic start with main topics like arrangements, puzzles, distribution, syllogisms etc. Make sure you do this properly.
For quants: visit all the tenth and twelfth formulas thoroughly. Start with topics like number systems, geometry, trignometry, percentages, averages, alligations and mixtures as these are important topics.
After you have done the basics, spend at least one month doing this and then start with mock exams. One exam per week and analysis on the same day. Simultaneously strengthen and practice your above topics as well as wek ones.
After 3-5 months of this 4 hr per day practice you will reach the 95 percentile mark. You have to reach here. Because going beyond 95 is difficult and every percentile to conquer is a task in itself. You might even feel stagnated at this point. Yes this period sucks. You will not know which topics to improve to get to the 99 percentile mark. Well my suggestion is, you have to reduce the amount of time you spend per sum or question. To do that you need to practice religiously.. Your strengths first and then weaknesses. By now you know what topics you are good at and which ones are you bad at. 2 months are enough to cross 99 percentile barrier. Utilize this 7 months properly and you will have no regrets! All the best!

After you get good percentile in exams, you wo have to give personal interview, group discussions, etc to get into the desired college.
Also prepare for other exams like cet, xat, snap, mat, gmat(foreign mba), tissnet, nmat, etc because cat is a risky business and you don't want to put all your eggs in one basket.
Good luck!