Vaseline is magic for shoes that rub. I bought the cutest pair of flats a while back and they are just a little too tight (yes, I know, I should have bought the size up, but they were cheap so I thought the size up would strecth and fall off my feet immediately).
My best friend introduced me to the vaseline trick, and it really works! In case there is any confusion, you rub vaseline on your feet, put the shoes on and you're good to go!
This of course should not encourage me to buy shoes that are too small, but might help me break out a few discarded pairs that I love from the back of the wardrobe!