What are some good ways to promote a blog?
Up-front, I should disclaim the fact that this really isn't my area of expertise. That said, I do have an answer.
Basically, it comes down to this. You need to learn to get really good at SEO.
Mostly this means you need to write great headlines that accurately describe the content of the post, and do a lot of targeted meta-data tagging.
But more than that, I think it's really just about having great content and updating regularly and often. The more content your blog has, and the more times people visit it per day, the better it does in everyone's search rankings... So produce content people want to read and do it every day. That's by far the best way to promote a blog.
Also, you can ask other - more prominent - bloggers to link to your blog on their blogs, if the content makes sense for their audiences, and there's always the option of just buying advertisements and promote it with cold, hard, cash.
I would add to this one important thing.
Do NOT just spam links to your blog on every other platform that's more prominent than yours.
It's super annoying, and it doesn't really help you get more blog subscribers anyway since it turns off potential readers and because the same IP address posting the same links over and over doesn't get you anywhere in search engines anyway.
All that said, I probably have some friends who can offer a lot more advice, since this really isn't what I do.