It's essential to read the project's white paper. It shouldn't be just brilliantly written with no grammar errors and stuff, but WP is the thing to know the project much better and evaluate whether it's scam or not (WP written really poorly, lots of copypasting and so on). WP was invented to explain the idea of the project to us, ordinary people, and I think it's really necessary thing. Hugely potential projects (EOS, Bitupper, Cardano, NEO, ETH itself) have their WPs to bring the project into the masses