In my opinion, the likelihood of success with non-surgical options depends largely on several factors: (1) how bad it already is. (2) how long you can stand the self-imposed inactivity while you heal. (3) whether you work on your feet or not. (4) how diligently you pursue PT, icing, stretching, etc. -- all the non-surgical means of getting over the injury.
In my case, I've had plantar fasciitis on both feet (not at the same time), and in both cases ended up having "endoscopic plantar fasciotomy" - surgery. The plantar fascia is partially severed. After it heals, it is slightly longer - thus relieving the tension that causes the inflammation and pain.
Surgery is the "nuclear option" - I did this after several attempts to heal, involving cortizone shots, physical therapy, rest, etc. Sometimes I thought I was over it, but then the pain would slowly return. So I guess I lacked the patience and the self-discipline to get through it without surgery.
The second time, I did not wait as long. I'd already had a successful surgical outcome, and I trusted my podiatrist to "get it right" one more time for me - and he did. I am 100% satisfied with the results.
But I'm
not saying that the non-surgical options won't work for you. Just that they didn't work for me. After long (and very frustrating) periods of self-imposed inactivity, I'd get out running and hiking again, and the pain would slowly return.
And I'm
not telling you to go get surgery. That is a very serious decision and one only you can make, together with your doctor(s).
If it's bad, and if you really want to get past it, be prepared to stop weight- bearing exercise for as long as it takes. You'll need a lot of patience. PT helps, as do all the various methods (icing, stretching, massage, etc.) already mentioned here. No bare feet, ever, as has been said, and stay off your feet as much as you can.
One other treatment that has not been mentioned is to wear a "night splint" -a device to keep your ankle bent at a 90 degree (+/-) angle while you sleep. Bent ankle = mildly stretched plantar fascia = less pain when you first get on your feet in the morning. There are various types.
Here is one I found to be comfortable enough to wear all night.
Good luck! I hope you fare better than I did.