Ever heard of the book "The Artist's Way" by Julia Cameron? It’s a book that I found horrifying and that I did not finish, but which does have the merit of proposing a good idea: the morning pages.
It's about taking a few draft sheets and a pen and, for twenty minutes, every morning, writing down anything that comes to mind. These pages being destined for the trash, you must neither reflect nor correct, but let the thread of your consciousness unfold – from your brain to the paper.
For me, it typically started with "I'm bored, I have nothing to say... " repeated several times until the arrival of an often surprising or soothing "inspiration.”
I no longer practice this exercise, but I keep it in mind on the first draft I write without worrying about style, grammar or consistency. If I stumble for more than a few seconds, I put a question mark between two square brackets before continuing. I thus obtain a wobbly, but spontaneous outline, which I then improve in many successive passages.
I hope this inspires you to try. If you do, please do not hesitate to share your experience in a comment or in an email.