SlayZombi
I Love YTtalk
Yahoo! Answers
That may seems ridiculous but it really helps. Just DON'T SPAM. Answer questions you think you actually know about and it'll help them. In return, if you leave your link in the sources box, they will probably check out your channel.
Quotev
You've probably never heard of this, but it's a Facebook App that allows you to make quizzes to share with everyone in the world for free! It's really good because if you make a really cool quiz and leave your link in the final result for them, chances are they will think your channel is cool too!
Facebook
Posting your channel link to pages where video sharing is accepted can increase a lot of attraction for your videos! Post it on your timeline and on the most popular pages on Facebook!
Twitter
Twitter kinda sucks for this but if you already have a lot of followers, just keep posting links and they'll check it out.
YouTube
This is only for the truly desperate. If you really do believe you channel is going nowhere, post links across YouTube. Again, I REALLY DON'T RECOMMEND THIS, as it will p**s people off if your channel really isn't good.
Hope it helped~