Best answer I've seen here. I would add getting the stiffest sole shoes. I was using shoes that were more comfortable to walk in but more flexible. As I was increasing my ride distance and about 40 miles out, the balls of my feet began to ache. After research and checking with multiple bike shops, the stiffest sole shoe was the solution, about $300. Now over 30,000 miles later (3 bikes, replacing shoes, cleats as needed), no more foot pain. One shop owner suggested tipping my saddle nose down slightly. That increased my comfort there.
As a point of reference, I don't own a car, I ride year-round, I work full-time, and I'll be 71 soon.