Invite someone from YouTube to make a joint video. It's the best way to earn an audience. When you are both popular with different people, you exchange audiences. When only one person is popular, it helps both the guest and the audience because both get new topics for discussion.
Make the most of your social networks. Get your friends involved in promoting your content. It helped me a little to promote my channel because I turned to old friends for help. Some of them have quite a large audience on Facebook or Instagram, so a certain percentage of their readers could see my content as well. I once paid to promote a video to this company tubeboost.net. I felt like I had made such quality content that people SHOULD SEE IT. Well, people did see it, but for money, haha. I don't believe I could push my video to five thousand views on my own because I don't have a stable reputation on YouTube.