How to maximise my chances of selection in IIT-JEE??

First you need to concentrate on your strong points and you can take help of various resources available to you including teacher, friends and tutors. Also, try to visit online educational websites like http://askiitians.com for your preparations.

Time management is not a big issue once you start working on your subjects and topics.

in beginning, you always feel that you are not following proper schedule but with time, you will be synchronized with schedules and you will be on track for your preparations.