I've been making videos for about 9 months now, and I have gained over 350 subscribers over the past 2 months. I have one video with over 10K views, and it drives about 30% of my views. When you are in a niche, find something coming up that is going to be popular and do it as soon as possible. For example, I make Pokemon videos, and there is a new Pokemon game coming out on Nov. 21st. As soon as I get my hands on those games, I am going to start a Let's Play of them on my channel. If I get it out early enough, I can drive a ton of traffic to my channel because I will have my episode 1 at the top of the search. I don't know what niche you are in, but you could find something similar to that, and it would probably give you a lot of exposure.