Often, I find new solutions to hard problems when I change something about my environment. I switch from a big monitor to a tablet screen, or the other way around , and suddenly, it’s obvious how to get something done.
Sometimes, I go to work from a cafe or a library, and it also brings a fresh perspective.
Work in silence (if you can afford such luxury) or with music. See what works for you; try something new from time to time.
There is also value in a solid routine, but a healthy dose of variation can help you in surprising ways.