We Ultrarunners are understandably cognizant of how tough our feet are.
In my first 100 miler I had no specific system for foot management and as a result paid a huge price in terms of HUGE blisters that covered most of the bottoms of my feet. Self-inflicted, of course, but it was quite an ordeal.
In this post I'm not going to get into shoes, socks, duct tape to protect the feet (I'm not a fan), etc. I'm just going to provide one simple tip that has worked for me.
Go barefoot. No, not on your runs--to me, that's insane. I'm suggesting you simply go barefoot around your home and yard whenever possible. You'll toughen the soles of your feet over time.
And do it under poor conditions. For example, I just walked down to my mailbox to get the morning paper. It's probably 200' + one way, close to 500' round trip...in other words, nearly 1/10 of a mile. The temp was in the upper 30s F. This definitely stresses--and thereby toughens--the feet.
Now, I don't do the mailbox thing Valley Forge style when there's snow on the ground (although I suppose I could), but barefooting it to the mailbox is my normal routine all year. Give it a try.