It really depends what you mean by “writing for yourself”. I think everything I’ve published here on Medium, I wrote because it was something I felt moved to write, and not specifically because it was something I thought would please my readers. I’ve responded to writing prompts (I write mainly poetry and fiction), which may guide the topic, but ultimately what I have written and published is what interested me at the time. I think the missing ingredient you neglected to mention is, how well you write about what it is you wish to write. What I don’t do is publish half-baked thoughts; anything I publish here has been well-crafted, and to a level I consider worthy of publication. It is possible to write about the minutiae of your life and still engage readers – it all comes down to your skill as a storyteller. So maybe it’s less about thinking about what your readers might want to read, but instead think about how you can tell it in such a way as to hold their attention.