I always follow my favorite bounty managers and participate in all their projects. Often this is the best choice, because you can be sure of their quality and that you will not be deceived. Maybe there are more options, but in my opinion this is the best choice.
Actually this is I think as a very good method of identify a good project. Good bounty managers them self analysis the project before accepting the job. Therefor following good bounty managers are worthwhile. With this we can also refer other aspects such as rating of the project and project documents as well.