1. Join a bounty project promoted by reputable bounty managers here. You can try to search a thread here in the forum for them and there are quite few results of them in a list form.
2. Do not be greedy and put too much trust on the project. If you can earn then good if not then let it be. As long as you get a reward then that would do already. If you try to join all of the bounty in that project then it will be a load of work and if ain't pay you then that is really a waste of time and resources.
3. If the team offering the bounty hunters to pay a small amount for the bounty hunters to process the rewards then pretty sure they are scam. They just trying to scam even the bounty hunters.
4. Join an organized group or team handling bounty projects scrutinizing the project before accepting will likely to be legit.
5. You can search google for incoming good projects but some of these projects are not offer here in bct instead they just use other platforms to promote the project. However some offer the project has offer it here in BCT so it will be a  good chance to join that kind of project.