I assume that from some basic things you can guess that a bounty campaign is a scam, for example when someone finds that the white paper is plagiarized, or that the team behind everything is completely fake. Therefore, if you want to increase the chances of participating in something where you have a chance to earn something at the end, you should research each campaign - which is certainly not an easy job.

I would recommend that you instead read more posts and learn from more experienced members, and this will eventually result in you getting a place in some sig campaign that pays in BTC.