Came across an excerpt from nature writer Henry David Thoreau I hadn't previously encountered. This observation applies not only to day-to-day living, but also when one's focus in on an artistic or creative enterprise:
"As a single footstep will not make a path on the earth, so a single thought will not make a pathway in the mind. To make a deep physical path, we walk again and again. To make a deep mental path, we must think over and over the kind of thoughts we wish to dominate our lives."
[thanks, Mohonk Preserve]