I posted this somewhere else but I'll repost it here.

An airdrop is worth NOTHING if the coin you are receiving is worthless. I could create an ERC20 token today if I wanted, and give away 10 billion tokens to each person in an airdrop. The problem? Those 10 billion tokens are worth absolutely nothing. They may as well not be there as its simply a number in my wallet. 

I would say 90%+ of the new coins out there are/will be worthless. Before even considering joining a bounty campaign or airdrop, I always look at a couple things:

1) Does the coin I'm receiving have a purpose/goal?
2) Do the developers have credibility/experience?
3) Is the announcement thread written in proper English and formatted well? (seriously this tells me a lot)
4) Is there a masternode pre-sale? (If yes, don't even consider joining the project. Seriously, look at my signature and you can tell how much I hate discord masternode pre-sales)

If a coin doesn't meet all of the criteria above, I don't even bother with it. If it does, I will do more research, and if the project sounds promising I will participate in any airdrops/bounties they do. 

The key to finding success in airdrops/bounties is quality, not quantity. If you participated in the 1000 ONT airdrop, you probably made more than joining 500 random shitcoin airdrops. Be selective!