If you have some skills such as writing , designing , developing websites or apps then you could offer like a service on the forums for BTC or you could simply rank up with time and that could take a while until you reach full member rank and enroll into the sig campaigns to advertise other services and get paid for it.
AS I M A NEW MEMBER WHAT SHOULD I DO FIRST. AND I DONT HAVE ANY WRITING SKILL . HOW CAN I BE READY FOR TWITTER CAMPAIN .PLEASE TELL ME...
As he said you can simply rank up until you reach higher rank then try to apply into the signature campaign to advertise other service and get paid.