I've had a half-dozen career shifts in the past 15 years, and as a result have had to adjust to new things to think about while incorporating new ways to think about them.
One thing I've always come back to is this: if stuck on a problem—be it creative, analytical, or otherwise—go for a walk. Or a run. Or a cycle. It doesn't matter. Put literal miles between you and what's blocking you. Make your brain focus on moving your body.
Regardless of whether I had been running or walking, the two-mile marker was almost always where I thought of a solution. I was able to return to the problem fresh, work on the solution, and move past it.
Pulling your hair out? Pouring a sixth cup of coffee? Skipping meals? Put it down. Take a walk.