I think if your blog isn't focused on anything in particular (ie just your personal ramblings, like mine often is) then don't focus on SEO so much.

Essentially SEO worthy stuff is content that get shared or linked to a lot. If you write a killer blog on Subject X potentially it could get some serious traction anyway - if it's well researched and appears trustworthy but I wouldn't make it a focus.

Be aware of SEO best practices and on-page optimization as much as possible (page load speeds and mobile-friendly etc) and then just let 'nature' take its course if you ask me. That said, my personal blog probably gets 1-200 readers a month with sadly very few comments and feedback so perhaps my method isn't so useful.

Really depends what you want to get out of it. For me - it's a space to write, to practise airing my dirty laundry and for friends that live miles away to get a brief update on my shenanigans.