Trading is great way to earn bitcoin but along with there are many innovative tools to earn bitcoins as I personally build two information sites especially related to bitcoin and getting good earning by selling adspaces. In this proccess need little investment but its has exponential potential.
Yeah,earning bitcoin in not only investing and making signature campaining,there are a lot of skills you can offer to people here,and they will pay you for them.
For example,if you have good rank,well known account here you may start an escrow service,or look ppl who need's escrow.
https://bitcointalk.org/index.php?topic=1244332.0 check it out guys!