If youre serious about Airdrops I would suggest you make a Bitcointalk forum account to be able to apply for the airdrops that require contacting a team member (usually PM). Ethereum Dark airdrop is a good example of this format. Every person that wanted to apply for this ETHd airdrop had to PM the developer with his ETHd address to get the tokens.
Newbies on the forum are often rejected for new airdrops, so we suggest you post once in a while to get a higher rank.
Yes you should be active.
Keep in mind that most airdrops are for nothing. Just to get you like a facebook page or a follow a Twitter page.
I noticed some airdrops are raising Telegram users in order to have a group to post about other ICO projects to get into the bounty campaigns.
Stay Away!
That is a common thing too i guess, but if you do a good research and read whitepaper if there are any you should be good.