Proper fitting shoes are really important. I had a ton of blisters when I went (they started the first full day) and I found out my shoes were too small. Got new shoes in a bigger size, no blisters.
I highly recommened getting some cool-max socks--they whick away the sweat (which can also cause blisters).
moleskin or bandaids for hot spots. Moleskin works great if the hot spot is not on a toe, but for me bandaids work best around toes. I also like to put Neosporin + pain relief on toe hot spots for the pain.