Hi AF. Sounds like you're already working hard, as advertising on social media is a great way to go. Being involved in the community, like with answers (which we're doing now!) and forums also helps.
But the vast majority of traffic should come from search engines to provide consistent and steady viewership. To do so, write using searchable terms, and it helps to cover subjects few others talk about. Backlinking to past Hubs is also good as long as it fits the context of your Hub, so it doesn't come across as spammy.
Best of luck!