Best option in my opinion is signature campaigns.
Its maybe not the best option but it certainly is the easiest option for earning on bitcointalk, there are many other ways for earning more then signature campaigns but you may need some skills for that but for signature campaigns all you need to know is about bitcoin and anything related to it.
For me it's the best way and the easiest way to earning bitcoin on bitcointalk. especially for you that like post something on this forum, so it's like a bonus for your posting.
Most of the users feel this to be the best way to earn bitcoin. Bitcoin has also got various methods to earn. Only large number of users can be seen in forum than in trade and other means.