It seems that blisters are one of the most popular topics here, on par with bedbugs and albergue races. This may not help solve your personal blister problems, but I can tell you how one person finally did a trip without them.
My wife gets blisters just looking at hiking trails. Some people’s skin is like that. I have to really abuse my feet to get blisters, but she can hardly avoid them. She gets them under her feet, on her heels, between her toes, everywhere. All this despite the fact that she is a geologist, with a lifetime of hiking and backpacking experience.
This year we planned two big hikes: a 17 day walk in France including the Robert Louis Stevenson Trail, and a 22 day trek in the Nepal Himalaya, around the Manaslu circuit with a side trip to the Tibet border in the Tsum Valley. We did a lot of preparation, and tried a lot of the ideas found on this great forum. Here’s what worked:
Hiker Goo:
http://www.amazon.com/HikeGoo-Blister-Prevention-Specifically-Formulated/dp/B008RRXC9O
This glop can be smeared all over the feet, and cuts friction. It is not a gross in the socks as one might expect, and a tube goes a long way. This stuff helped prevent the heel and side-of big toe blisters.
Microplane Colossal Pedicure Rasp: As callouses build up on your feet, the thick, stiff skin can be a problem of its own. This device will shave them down very nicely. It prevented the big under-callous blisters.
http://www.amazon.com/gp/product/B008A1TI4K/ref=oh_aui_detailpage_o06_s00?ie=UTF8&psc=1
Keen Industrial Shoes: My wife has really wide feet, and regular Keen hiking boots are among the widest available. Keen shoes have almost cult-like following among people with wide feet. A little known fact, however, is that Keen also makes a line of industrial shoes, some of which are very much like the hiking shoes, but they are available in an extra wide width. Some of these shoes and boots have steel toes, but some are just like the hiking boots. I myself was able to go a full size smaller with the industrial wide boots and find a better fit. My wife went with the Flint Low, soft toe model:
http://www.keenfootwear.com/product/shoes/women/flint-low-pr-soft-toe/chocolate%20brown!woodbine
Neos overshoes: The trip in Nepal required some serious footwear for the higher elevations. We went over a 17,000 foot pass, in snow, wearing micro-crampons. There is no warm place to dry wet boots. She was unable to find a high top waterproof boot that did not eventually eat her feet. The Neos overboots pull over the lowcut shoes and offer a full vibram sole and are 100% waterproof. This let her wear the comfortable breathable shoes the entire trip and just cover them with the over boots in the snow.
https://www.overshoe.com/Pages/default.aspx
Nexcare tape: When we walked the Stevenson Trail, we had yet to find the industrial shoes, and her cramped toes got blisters between each toe. Before going to Nepal, we found a wonderful stretchy tape, and the wider shoes gave her room to tape each toe. This was the final key. After getting a blister the second day, she taped each morning and did another 20 hard days without another one. Milagro!