After Graduation you can apply for 3 years LLB programme for the top universities Faculty of Law Delhi university, Faculty of LAW Banaras Hindu university, Punjab University etc. The Universities have its own entrance exam for the programme.

Plan a strategy: It is a must to schedule a study-plan. An intensive preparation strategy is needed which includes as many as 6 hours of regular studies to crack the entrance exam. Candidates must study at least two subjects every day and must practice at least one vocabulary / English and one reasoning exercise daily.
There is no defined syllabus for GK and current affairs in this exam. You can focus on important awards each year  sports, science, literature and arts, Physical geography, science and environment, Important happenings in the area of the Indian Constitution or Justice system
Mocks form an important part of the exam preparation. Look for a good online mock test series, and aim to write at least 6-8 mock tests before the actual exam. Reproduce the exam conditions as much as possible.
You can refer to some online websites for preparation majorly for mocks ortherwise you will get the material offline easily.
Along with this, you should start giving lots of online mock test and analyse solutions of each one of the thoroughly which will help you in overcoming your mistakes and come up with a strategy to definitely improve your marks and percentile. It will also help you to know about your strength and weakness which will help you in attempting easy questions first, that will reduce your chance of committing a silly mistake in an easy question or missing out an easy question. Along with this, you will also get enough time to attempt medium level difficult questions which will overall increase your speed with accuracy which leads to increase your percentile.

Good Luck!