I write here on my personal website and elsewhere. I have a process. I think that anyone who writes regularly ends up with a process.
I believe a simple process is the key to great writing. My process is designed for great work with the fewest moving parts.
I won't write something unless I have something to say. Forcing words on paper doesn't work for me.
More important, a great blog post says something meaningful. It doesn't have to be profound, but it should not be junk for junk's sake.
Even writing about a boring topic, saying something meaningful is not boring to the reader. Beer brewers thought their process was boring until a copywriter wrote an ad about it. Now every brewer and winery talks about process and does tours!
This part is the most obvious. You need to just write the blog post. Head smacking right?
I start by going to Soundrown and turning on the rain sound. Then I fire up FocusWriter and start typing. I'm nerdy and I have FocusWriter make a typewriter sound.
I also use OmmWriter for the same effect.
Sound helps me write, so I use it to my advantage.
I write so the focus of an article is the one thing I want to say. I explain it and give context. I want the reader to understand that one idea.
I don't have a real word length goal. To me that isn't conducive to doing great work. Instead, I try to explore the idea and say what I want to say.
I write in Markdown. I don't worry about dropping links or images in my rough draft. I save my blog post drafts in a drafts folder as plain text.
A rough draft is not ready to be published. I always need to edit my work.
The most obvious edit is to read what I wrote and make sure there are no obvious spelling or grammar errors.
I then go through my writing and cut out content. Clarity and simplicity is the goal.
After that, I will run it through Hemingway Editor. This helps me see things I might otherwise miss. It has helpful guidelines that lead to clarity.
Last I to read it one more time to make sure it is good. If it's not, I will try and fix it.
I have my own web publishing software, so I don't use WordPress or something similar.
I go through the article and add links where appropriate and make sure everything looks good on the live site.
Right now I don't make much use of images, but on sites that do I search out a royalty free stock image to use as a post image.
I don't worry much about SEO in my process. If I'm targeting a keyword, I will put the keyword in the page title, article slug, and make sure the article is about that topic.
My promotion strategy is very minimal. I drop a link on Twitter, and I'll drop a link on Hacker News or a niche specific subreddit.
Depending on what my publishing tempo is, I will add it to an upcoming email I send out to my raving fans (both of you).
That is what my process to write a blog post looks like. I hope that helped answer your question on how to write a blog post.
The most important thing you can do is to just sit down and write.