I had PF for about 2 years several years ago. Several things helped me, so maybe something here will be helpful for you:
Try using ice packs on your feet twice a day for 30-60 minutes while resting them on the couch or ottoman. Definately use the arch supports or inserts. They may not seem to be helping, but I bet they are doing more than you know.
Finally, try rolling a golf ball under the arch of your foot back and forth several times a day per foot. This helps stretch out that muscle and strengthen it. It really does work!
Finally, and this is the hard one, for me it took losing some extra weight to finally get rid of the entire problem. Weight loss is so difficult that I put it off as a last resort, even though I needed to do it much sooner. However, ultimately this made the biggest difference. Some people with PF are not overweight, so this might not be your situation, but it sure helped me.