Start Early (But when? In which year of Degree? There is no definite answer to this question but data suggests that Pre-final Year is the most appropriate time to start preparation)
Conduct Strength Weakness Opportunities Threats (SWOT) Analysis to know about yourself
Prepare a Plan accordingly and follow the plan. Track it on regular basis.
Plan can include strategy for 15 months (9 months: 4 months: 2 months)
Prepare your own notes (for in-depth study of the subjects): Long Notes / Short Notes / Flash Cards
Refer standard Text Books for detailed study of the subjects
Revise at regular interval and evaluation your performance through tests
Go through the syllabus
Prepare subject-wise Notes / Prepare every topic in depth
Prepare short notes for revision / Revise at regular interval
Clear doubts regularly / Give Mock test at regular interval
If possible form a group for studies / discussion