Just check their bounty pool, team,group in Telegram and make your own analysis to detect some scam signs.There are only few persp prijects with bounty.
Devs understand that bounty became inefficient
Indeed there is no strategy set in choosing a bounty campaign. Certain parameters must be viewed. This includes conducting project overviews or ICOs, reading team member profiles, considering their past performance and at the same time doing induction research on white paper.