Matt Gemmell has some solid tips that you can try the next time you sit down to write. Two tips in particular that I’ve done for a long time are:

I have a habit of adding a bullet-point right after I stop, briefly outlining the very next thing that happens. The following day, I just transform it into a sentence or two, and I feel that I’ve at least started.

I actually do this throughout my stories. As the story evolves, I think of things that need to be added or points that need to be made. The problem is, if I stop and add it in, I lose my momentum and I don’t like that. Sometimes a single word will be enough to jog my memory and by the time I’m finished, all of the relevant points have been made in the article.

Just trust yourself. Something will emerge. Unplanned structure.

For me, it’s not necessarily lack of planning, but lack of putting it on paper. I formulate my ideas in my head—sometimes for days or even weeks—before I ever write anything. When I do sit down to start writing, I have a flow that gets me through the toughest part of the article.