I believe that without signature campaign you probably could earn through the freelance work or offering goods and services, check the services section.
Actually if you are going full time in collecting bitcoin, you should always aim for those freelance jobs and your last choice should be signature campaigns and faucets...Cause if you focus too much on signature campaign you will not wake up to the truth that you could earn more outside the forum and in real life, but since we are talking about things that we could do in here to earn, I think those job offerings in the services section are the ones we could rely on without a signature campaign...
Exactly, signature campaigns are just the most common way to earn here since most of people do participate to earn money without any skills needed just a pure post with understandable english grammar and must be constructive. Same as they said there are lots of ways to earn bitcoin in these forum not only in sig camps but also you could sell your skills and you could also sell digital stuffs as you want. Just try to go in services section and you would find what would suits you.