Winger94
Super Poster
The slow way - visit other similar channels, sub, comment, engage, share their content on G+/FB/Tw, build relationships and they will in turn sub and share your stuff.
Well I'm using this way for now. I know that maybe will lead nowhere and I'm obtaining lower results, at least compared to other channels that have the same age of mine but obtained much more. I think that using this way you can grow more than a sub-base, something like a community and I think it's the best thing.
I want to create a bond with the members of my community, more than having a tons of views and nothing else!