First of all you should be aware of the exam syllabus and the pattern. After that you have to make a schedule to study all the subjects in the required timeframe and give enough time to practice the questions also.

You should start reading books highlighting the important points and also start solving the previous year questions . You can take enrollment in some coaching institutions or study on your own. You should revise regularly the concepts and start giving mock tests.

Hope this resolves your query.