There is not one way that fits all but for me there are just a few things I look at;
The team members behind the project are one thing, they tell you what kind of project it is, if they are serious about it
Then the whitepaper is one thing to look at, they are usually very long so you don't have to read the entire thing, just look at the spellings, the professionalism of it, that should tell you a lot
Then the roadmap is what tells you what they plan on working on in the future and how they plan to go about it