Been to Disney for over 75 days in 3 years and never had a blister!!!! We do the parks regularly but none of us wear sneakers or socks. I purchase shoes for the family about one month prior to trip. Wear every other day for whole day to break in. Usually buy deck shoes for the men in my life and sandals or loafers for me. (I buy a high quality shoe, that matters too).
Bring 2 pairs of shoes (along with the one's we have on). I alternate the shoes daily! I also think the deodorant spray is a great idea. I never understood why people wore socks and sneakers. Toes are too crunched up in a structured shoe.
Be comfortable and allow your feet to breath!