Self promotion is pretty much essential but you have to be careful about how you do it. As the lads above me have said, you can't just go somewhere and start begging for views.
The best self-promotion I've found is just to get active in communities and forums. Comment on things that interest you or you have an opinion on and leave a link to your channel in your signature or at the bottom of your post or something. Curiosity will get people looking, specially if the link is right there.
I'm still new at all this, only been up and running for about a month and I haven't really promoted a great deal or linked up with social media yet, but the channel is slowly growing. I guess I need to get on Reddit (@TheSwedishTraveller I'd need to find the gaming section but man, how do you navigate reddit, it's like the most cluttered unintuitive site I've ever been on!) and make up a Facebook fan page but this is all stuff that comes in time.