RULE NO 1. To avoid Phishing attempts, don't use your email password on the forms - If you can change your password once in a while.
RULE NO 2. Don't give away your private keys.
RULE NO 3. Dont just apply for Airdrops, read about the project, ask questions and if you are in a position to help do so - Dont forget to apply for Airdrops
This is another thing, don't just send asking amount from anonymous that works for the airdrop.
Don't get also be deceived by those people who are posting on twitter posts that are saying they have received the airdrop or free money after sending ETH/Bitcoin to the said address.
All of those that are commenting that they have received are fake and don't be fooled by those lazy scammers.
Better that if you just don't join those airdrops.