In srs though, it's all about making videos that you think people would actively search, rather than just making whatever. Thing is, even if you make the worst video, if you title it right, have good SEO, and your targeting a specific search that you think would be getting a lot of traffic, you can still get a very large amount of views.
And if you do happen to make very good video that lands a spot in traffic, a lot of those viewers subscribe.
...Is the over simple way of saying it. But you need to take that mindset into every video you make. Self promotion only takes you so far.