For me it's the whitepaper. In essence, you can see their intentions from reading their whitepaper. You can also spot unsuspecting things from the team by reading the whitepaper. For me though, I decide in the whitepaper to see whether the project is being handled by 15 year old monkeys or a dedicated developers. Well, we have our own preference, this is just mine.
The white paper is always good to read the news about the company and their future deals about the project, till now I have gone through many company white papers and failed to lead that development, not only Whitepaper we should keep track the team in all possible ways. I will trade coins when it is listed higher volume exchanges.