Top Down learning is studying a lesson first and then solving problems. Most of the time you are doing it in all complex subjects and topics.
Bottom Up learning is trying to solve a problem and finding new issues which are to be used in solving the problem. Everybody needs to engage in bottom up learning also. Top down is not sufficient.
Solve all problems of past JEE examinations at least five years 2009, 2008,2007,2006 and 2005 and engage in bottom up learning.
Now it is the time.