One good way to HELP toughen your feet is to use rubbing alcohol on your feet at night before you go to bed. It helps dry out the skin and make it tougher.
What's A Good Way To Toughen Up The Soles Of Your Feet?
That is my experience. Walking barefoot! First around your house then in your driveway and even try some gravel for short forays. I used to have feet so tough that I could walk through all kinds of debris without cutting them. HOt sand in small doses. The more you go barefoot, the quicker they toughen. If you can safely walk in flip flops, that helps a little. There was a time I could climb fences and run in them. Hope this helps! 
I do what you do, I walk around my house in bare feet (I know it's not healthy). I also walk outside on my drive way in bare feet. I heard walking on sand will toughen up your feet.
Apply surgical spirit to the soles of your feet to toughen them up, according to my great grandmother,& my chiropodist
The true best ways are walking around barefoot. Outside and inside. Walk on different textures(rocks, sand, cement, ect...) that will toughen them up. I really don't think there is any other way!
Epison Salts you can get it in a chemist bath your feet in water mixed with epison
Sandpaper your feet til they callous.