Firstly determine the success of the project before join it. I think that it is necessary to choose the program according to the same criteria as investors.     I'm participating in a German project Vreo.io, I am pleased. There is enough information on the Internet about the criteria for choosing Bounty.
The main ones
1. Uniqueness, necessity of idea
2.Clear target
3.Scalability
4.Transparency, properly allocated budget
5.Concept
6.Team
7.Distribution of tokens