You must follow trusted projects or trusted managers that will increase chance that you join airdrop that will actually pay you later.

The bigger issue is most of airdrop does not have good value. It can be few cents or nothing because coins or tokens you receive from airdrop are useless.

Sometimes you can get luck with airdrop from successful project or just a scam project but successfully scam investors. In general, I don't advise you to focus on airdrop. Many better things you can do than airdrop.