Have the wherewithal to fix a flat while on the road... or good walking shoes.

Each of my bikes has a little seat bag with a couple of tubes, levers, patch kit (yeah, I know, belt and suspenders), and wrench to remove my wheels, which you might not need, and a little folding tool thingy. And a little pump.

I know a lot of cyclists who are not comfortable with servicing a tire quickly while on the road. That's OK, but you can still use all of that kit to fix the tire when you get home, and eventually it will become routine.