I've found that writing a blog post is one of the best ways to learn something deeply. So I write stuff, not for marketing but own my personal development. Of course marketing is nice sub result, but I never focus too much on title like the OP.
My process looks like folowing
- Choose the subject (usually a very small topic or algorithm)
- Study it deeply for at least a weak, sometime months.
- Start writing the post, learning is still happening.
- Finish the post. At that point I usually have a very good understanding of the topic.
Never think that you can't write about a subject because you are not an expert. You may not be an expert but there are more people who know less than you and they will find the post worthwhile.