You can start a nix-shell and it will have Jekyll available in it for rendering the markdown articles locally.

You can put your half done articles in a ./_drafts folder first, but to render them, you have to start jekyll with an extra option:

jekyll serve --drafts

Articles should start with some summary paragraphs, which are shown on the blog article index page. Jekyll call these excerpts. Their boundary is marked by a <!--more--> comment tag.

The beginning of the article should start with a so-called YAML front matter to provide some meta information about the blog post, mainly the title, so don't start your text by repeating the title text as a markdown header.