More exercises for plantar fascitis are aimed at improving muscular support of the foot by practicing activating the intrinsic foot muscles, this can be done in sitting in bare feet and trying to press the pads of your toes downwards keeping all the toes straight. Aim to press all the toes down with the same pressure. its not as easy as it seems. If your toes curl then you are using the wrong muscles.

you can also practice balancing the pressures on the base of your feet whilst in sitting imagine a point on the middle of your heel under your foot, a point under the middle of the big toe and a point under the foot just behind your little toe. These points make up a tripod. Try to press down on all tree points to get the tripod effect. Practice rolling from the two points under the front of your foot keeping some weight on the heel point. Good foot muscle control can assist with solving the problem

If you cant do these then you need to get more expert help and keep practicing,

Good luck