Advertising externally is very ineffective in most cases. Since you're just poking your finger at the fat blob that is a community of other YouTubers.
To get noticed, you must go where your target market is, and that is most certainly not on these forums, social media sites, etc.. All you find there is other YouTubers, if you have something to offer the YouTube minded person, you'll get some hits as I did when I made a YouTuber-oriented video.
I see you do gaming, that means you should be going to places where gamers are but YouTubers aren't. Which is difficult to do correctly.
Comment sections? No.
Reddit? Most places for gamers have rules against posting videos.
Google+? People use that?
Twitter? Sure, hashtags are alright, but don't try to drag people in by tagging their name.
Facebook? Maybe. But not in the comments section.
It is difficult to advertise appropriately, the only real way to do it is with adsense, but that costs money, so these free, ineffective substitutes for an otherwise working system will have to do.