Just stumbled upon this interesting video course on blogging. It looks rather promising as the focus is on creating content that should attract more business. It also from rather credible people who know what they're talking about.
Check it out, if this is something you're interested in: https://ahrefs.com/blogging-course
P.S.: They might also try to upsell their SEO services, but I guess that's a fair price to pay when you try something for free.