As an ex sufferer, you need 4 things:
1) tennis ball
2) cricket ball
3) golf ball
4)Some good insoles
Every spare moment you get roll one of the above under the instep of your sole. Apply as much weight as your pain tolerance can bare at about 8/10 threshold. Work it and work it. Stretch your calves as often as you can too. Start with the tennis ball and work your way down the list as things improve. Do it as often as you can and if you’re feeling motivated add in contrast baths of iced water (10mins) and warm water (5mins) 3 or 4 times an evening. Waring some good arch support insoles is a must. I always wear footreviver insoles because I have found them the best for plantar fasciitis as they support my feet in just the right way.
Stick with it and good luck.
Ps do nothing and it won’t just get better on its own!