What Mark, Annie, Gerard, Viranani and Bystander said...
(Sorry; couldn't help myself...It was too fun not to keep the circle going!)
Here's how you don't get blisters:
Walk 10 minutes.
Stop at bar/cafe. Take off boots and socks. Drink cafe con leche. Rest for an hour.
Put books and socks back on. Begin walking again.
Repeat every 80 minutes.
You'll never get to where you are going, and/or you will be on the Camino for a very long time, but you'll be well caffeinated and will be able to give really good reviews on all of the places to stop. Oh and you will not experience one single blister.
But seriously...
I think it depends on how long you walk in a day and what kind of surface you walk on. On the
Camino Frances in Oct/Nov, I wore Keen boots with a variety of (wool, silk) sock combinations and blister aids: I got blisters. Lots of walking surface types. On the Camino Portuguese the following Oct/Nov, I wore sports/hiking sandals with a variety of looks--no socks, socks, two socks and blister aids: I got blisters. Lots of types of walking surfaces but a great deal of asphalt roads to contend with.
I think the way to go is to be aware of your feet as they go--stop every 10 km +/-, change your socks and air out your feet if you wear boots or the oh so chi chi socks and sandals look. Or just air out your feet, if you go with just sandals. That is what I learned in Joyce Rupp's book (Walk In A Relaxed Manner); she claimed that she and her friend never got blisters by following this method.
You also have to really really stay on top of the hydration. Drink lots and drink often. I'm talking about water here!