Hi, all, toppers of this year, congratulations to you for your success.
Now, many of you have got good ranks which is enough to get a TA position in top IITs. Some some of you may have to face RA interviews.
In most of the IITs, the autumn semester starts from July. Considering that, you have ample amount of time to learn something relevant to the topics that you are willing to pursue in IITs. This would help you to decide your area of interest ( for your master thesis and seminar and all ).
There is a Moodle site called "go-classroom" ( http://classroom.gateoverflow.in) initiated by Arjun Suresh Sir last year. You may join the M.Tech section to get updates related to M.Tech courses, relevant lecture, assignments, useful links, and many more useful stuff.
The section is not updated yet, but it will be updated soon.