The link below is an article, whose title "The secret to writing incredible blog posts" is a real click-bait. But it is just so plainly useful that I recommend you reading it for its 3 basic-but-ever-so-true pieces of advice:
1 - Write about what YOU know
2- Write about UNIQUE experiences that you had
3 - Be concise and HAVE A POINT
"People always ask me what they should blog about. Should they write about this fancy topic? This complicated process? This trendy thing that they don’t really know much about but everyone is talking about it?
No. No. NO!"
3-mn read: The secret to writing incredible blog posts (Medium)