If u ask about only for the Airdrops then u must visit and like Airdropalert on Twitter. But if u want more to earn then there are lots of bounty campaigns are running. From those i tell u one good bounty which is running in its second round till from 18 January to 22 march. So be the partner of this bounty and take good rewards by Signature, Facebook, Twitter Campaigns by simple tasks and click on given URL for whole detail.
https://bitcointalk.org/index.php?topic=2197521.1520