Here are my foot tips....
I have trouble with my toes...specifically, my fourth toes, which get squished under my third toes and get blisters on the bottoms. Weird, I know.

Anyway, I read a tip somewhere that said to use corn pads with band-aids or moleskin to help prevent and treat blisters. I have used them my last two trips and had absolutely no problems.
Another fantastic tip I read was, if you do get a blister, apply a corn pad so the blister is in the middle. Then, fill with Neosporin or the like and cover with a band-aid or moleskin. This provides extra protection and comfort, so the blister can heal.
Also, I found some really great socks before my last trip, with extra padding at the ball of the foot and the heel AND with arch support. These are by far the best, most comfortable socks I've ever worn. My feet never got tired from walking, and I was with a 6 yo and 2 yo!

I got them at Target (can't remember the brand)...they are also made with a special fiber to help keep your feet dry.
Poohbear