The safest way for me is to join some signature campaigns, Bounty campaigns, or social media campaigns like facebook, Instagram, telegram or twitter. You can also join some airdrops but also be careful when joining. Airdrop require you to put your information that they will get your data and you must also aware that your private keys will only be going to be in a safe place, so never give your private keys to anyone. If some Airdrop will get your private keys then I assure you that they are scammers.