Hi,
I am new here can you tell me how can i choose good one for me...

A good one ...WHAT?
Wallet, Exchange, Mixer, Mining rig.. etc..
I assume you are talking about bounty campaign right?
Yeah i am talking about bounty campaigns...
Good bounty campaign can be considering by:
- Their team. Are they well known, profesional, and capable doing the project.
- The use of their coin. What is coin for, what business they going in and many would be interested later or not.
- Their community. Their support and everything behind the frontpage. are possitive and transparent or not.
- Their exchange or plan list on large exchange.
Hope this can help you.