In order to pick up a worthwhile project, just pay attention to what makes any project being a real project:
 - understandable and reachable idea and/or concept (something, what is gonna be useful/used by you/used by loads of people);
 - solid wp and understandable roadmap;
 - website;
 - presence of MVP;
 - linkedin profiles of team members (they in their turn must be very experienced and competent in the area they're working in);
 - media coverage;
 - active community support, etc.

These are the criteria of a promising and successful project, including one my most favorite - Cryptics. Check it out, it's the example of a trustworthy project