First i search the name of coin on COINMARKETCAP from there i saw the legit website of that coin..
Second i search the TELEGRAM GROUP CHAT link from the WEBSITE of coin
Not all coins are listed in coinmarketcap when the teams provide the Airdrop program. For new coins, they are absolutely not listed in coinmarketcap yet, the teams should fulfill some requirements to list them on coinmarketcap.
Yes, it is a good way to analyze its official website, especially focus to gain information about the team members. Don't join if the team members are likely fake.