The first, you have to do is find out information about a running bounty project and usually this bounty info is in the bitcointalk.org forum. But you do not need to search for it, just visit the following link: https://bitcointalk.org/index.php?board=159.0


You will see some Bounty like the picture above, please select bounty project that still running that you want to follow.
And you have to find out where the right Bounty does not look scam to follow. Most importantly check through the Website of the project