Insofar as sore feet from dancing is similar to soreness in other body parts
after strenuous physical exercise, strengthening the feet should help. Most
people are too busy to take time out for exercise, so one trick is to do it
while you are doing something else, sort of "free exercise". my favorite
time is the morning, while i am dressing, shaving, and (if you are always in
a rush, like me), eating breakfast.
Mainly i just do everything while staying on the balls of my feet. That gets
the calf muscles and anything attached to them. To raise the ante, i bend my
knees into a half-squat. that gets higher-up muscles.
and i keep my weight as low as i can. much harder than the above.