to prove they're not scammer project and minimize your investment of being scam...
1. look for the team if they're legit and real human... prove to yourself if they're human and real, not fake linkin from russia, reddit or facebook stuff...
2. list your find...
If they have a working product for the project that would be a great plus for me because that will make me a bit more comfortable with the project but, TBH finding a project with a working product is a bit tough.