I was quite fortunate for my channel. I do simulator content and whilst there aren't too many viewers in that area, they do keep coming back! I was also able to get myself a partnership with a fairly major company in this genre who are more than happy to give me free content (I choose, they give) and advertising in return for a review on whatever I've picked out. I may not be the biggest channel, but I have enough to get me going.
Collaborations are also ace! I do a weekly War Thunder stream with a couple of mates, some of the funniest conversations can be had during them and people just love it! Another way to keep viewers returning to your channel.
If you need any ideas, just have a quick look through my channel. I've got numerous social media, a website in the works and light but high-quality video editing going on. Overall I'm quite happy with how it's gone down, and I can only hope to grow in the next few months. (I have stunted a little however, meaning I will need to work on something major soon before I start to lose too many viewers!)