Funny thing about PF is that none of the most commonly-repeated remedies ever seemed to work for anyone I know who has had it, myself included.
How do you stretch it? When I had it bad, I noticed that I could do a straight-leg calf stretch pretty well, but it felt very tight when I did a bent-leg calf stretch. Also, only stretch it when it's warm. Massage your foot and calf well before you step out of bed in the morning and before you go to bed.
The quickest improvement I ever saw was from two exercises, though I'm not sure if it was one or the other that did it. Disclaimer: none of this is based on any research or advice of any kind, only personal experimentation.
1. Deep one-legged calf raises: hang your heel off of a step and very slowly go from a stretch into a calf raise. It's a stretch and a light lift in one (add weight if you want to). You can also start small and ease into a larger range of motion as you go through each set. I did them every day after my runs on both feet just to keep balanced.
2. Toe scrunches: This is basically just the exercise where you scrunch a towel under your bare foot using only your toes. I did a different variation where, while standing barefoot on a carpet, I would lean forward slightly and drag my heels forward on the carpet by gripping it with both sets of toes. Same as the towel exercise but much more resistance.
Last I had PF was last year (ALL of last year) and the first thing I noticed after exercising it was that my arches no longer felt tight when I woke up in the morning. Then the inflammation faded away even while I was still training. Haven't had a problem with it since, although I think I'll have to get back to my exercises before it shows up again.