I too used to have terrible toe blister problems! 450 miles' worth, in fact!
Prevention -
1) Liner socks are wonderful. If she has blister problems, in general, she should try wearing them. they're lightweight, wicking, and generally last for 500-800 miles per pair.
2) TOE SOCKS, however, were my golden ticket to blister-free happiness. The problem with normal wool or liner socks is that there's still skin rubbing against fabric, no matter how slippery the fabric is. However, if you're wearing toe socks, the fabric conforms to the shape of your toe, so it's toe sock rubbing against sock-sock. Seriously, if she suffers from toe blisters, I can't describe how magical toe socks are. Two years I walked into Damascus, Virginia, with oozing blisters on every single one of my ten toes. I bought a couple pairs of SmartWool toe socks at the outfitters, and have never had another toe blister since. Not one.
3) If she has persistent blister problem, she can try the LarryBoy extremely excessive and laughable solution - I only would recommend it if she's has consistent issues with toe blisters - Wear toe socks, inside of synthetic nylon socks, inside of normal hiking socks. Note, you'll look and feel like a goof wearing three pairs of socks (it's more like wearing slippers, actually). But I do it, and it makes all the difference.
4) Wash your socks after every day, even if it's just rinsing them out in a crick. Helps them last longer too.
5) Trail runners are generally kinder to blister-prone feet than boots are, as they move with your foot more.
Cure -
1) When you take your socks off at the end of the day, rather than shoving them into your camp socks immediately, let them air out for 15-20 minutes. Allows them to de-prune and keeps the skin in better condition. As others have suggested, this can/should also be done during breaks in the hiking day
2) Ditch moleskin; as she's found out, it's useless. Some folks use fancier tapes, and I have no doubt they work very well. However, I've always found good ol duct tape to do just fine. The key is in the application. Cut a long strip of tape, about 1/4 inche wide, and wrap it all the way around the toe several times in an overlapping spiral pattern. tape all the way to the end of the toe, so you don't get another blister in the place where your toe curls around the tape and pinches. Similarly, if you have blisters on your heel, wrap the tape all the way around the foot. This will the tape in place no matter how wet/sweaty/wiggle your foot is.
3) Cut the tape off every night and allow the foot to breath, aiding quicker recovery. It might be anecdotal, but keeping that foot out of the sleeping bag seems to help me, at least psychologically.
I've subjected my feet to some truly horrid conditions (walking through rain and knee-high mud continuously for several weeks, and with the above techniques, I've beat my blister problems. Hopefully your wife can find something that works for her!
