I use a lot of methods to research ico, before researching further I will look at the Whitepaper first, then I will check the team on the project, then partnerships and advisors. if all are legit, I will check how active the social media and telegram groups are.
Good filtering there I also use the same method. I even try checking the smart contract and its creator and see and identify if the owner is legit or just some airdrop guy. Most fake projects immediately sells their tokens or coins offering airdrops for ETHs. Some tries to fool by saying they are already listed but on decentralized exchanges which does not need any requirements and verification. I do participate in airdrops and mostly got disappointed since most are just there for decorations.