As full time or part-time bounty hunters identifying best bounties are very important since there is a tendency of increasing scam ICO''s now. Here I am giving some attention to following factors when choosing good bounties.
1. Rating- If the ICO has some rating. If this rating is good or high it is a indication that this is a good ICO.
2. Managers of the bounty- some managers has good reputation such as Amazix , Kripital etc.
3. The team behind the team -IF the team is strong and capable with good track record it is a indication that the bounty and ICO will succeed.
These are the main points come into my mind.
First thing I would look for is the team behind the project, check if they are not using false identities or something like that, also look for them on social media and their background. The second thing I would look for is the manager of the bounty, it is not exclusive, but if it has a high rank on the forum then that could be a great sign.