I've found that Google is the best tool for scam detection. You should be able to find at least some discussion on any legitimate project or service. You also get to read about people's unique experiences, which may also help you decide if you want to dip your toes in. Scams will have little to no discussion, and might even have people directly calling it out. You know how people do extensive research on some new phone or car before buying them? That's exactly the kind of thing investors need to do on their potential investments.

Websites that rate others' trustworthiness often use rigid metrics that can be gamed or manipulated. They could be useful for finding certain information, but should never be the be all and end all for deciding trustworthiness.