3) If you want different perspectives on various aspects of the CAT and subsequent GD/PI processes, then http://www.pagalguy.com is a really good and popular site. Pagalguy has a versatile community and a rich bank of knowledge stacked away in its forums.
Combine this with The Hindu, Thesaurus, as many test papers/sample papers as possible.
The best way to stay updated on the various developments is to follow specific sub-reddits.
/r/worldnews: Be updated on the current events in the world.