How to do.. a thing never done before
(You're going to trick your brain and write a thing. Win-win.)
Write a how-to sort of piece about how to do something that you have not ever done but that you very much want to do. Research it a bit and write it with authority as if explaining to someone how to do this thing that you’ve never done but very much want to do.
Nevermind why you haven’t done this thing yet. That’s not the exercise. But, after you’ve researched and written this, see if you aren’t even a tiny bit closer to doing that thing you want to do. Does it seem more doable now? Thought it might.