It is impossible to tell for sure, of course. But we try to go by the track records of the people involved, the project's partners and their reputations, the quality of the project's documentation, the level of their social media activity and so on. It helps narrow them down.

Generally, the more real details they are willing to provide about themselves and the more this information checks out, the better. That way, at least you will know that it is a real project that has some chance of success rather than a dud.