If footwear changes do not help your plantar fasciitis then it's time to get stretching.
The plantar fascia is a ligament and ligaments are not very stretchy so we need to stretch the muscles acting on the plantar fascia and the calf muscle group are often the main culprit.
Stretching the calf muscle can have a direct effect on your plantar fascia. Lunges and heel drops [standing with the balls of both feet on a step and lowering both heels down] can both help if done daily for at least a fortnight.
Using a wall for support keep your front knee vertical above your ankle and stretch the back-leg’s calf muscle. Keep the heel on the floor and both feet facing forwards, the back foot usually wants to tilt outwards. There’s no need to push into the wall and don’t pulse in and out, just hold for at least 30 seconds. If you cannot feel a stretch move your back leg further away from the wall.
To bring this stretch into your Soleus muscle place a rolled-up hand towel under the ball of the foot in the leg you are stretching. Again, just feel this stretch and hold for 30 seconds.