If I just have the teeniest hint of “Plantar Faciitis” while backpacking I immediately lift my toes and walk like that (with toes up). That seems to nip it in the bud. But to keep it in check I do the following:

1. lift and stretch like PerryMK pointed out.
2. make sure the shoe arch (and there needs to be one) is smack centered on the foot arch. And when you go from thin to thick socks (for those cold mornings) make sure the arch is still centered; or your foot will never forgive you.
3. Sleep with toes stretched back so you won’t wake screaming in the morning from the pain. Do not sleep in the pointy toe ballerina position.
4. And that squishy heal thing that Gershon mentioned really helps. All these people that use ‘minimalist’ shoes lose that squishy heal.

BTW, even though I’m a sandal wearer this is true with all footwear.

Good topic.
-Barry
-The mountains were made for Teva’s