Begin teaching recall with short distances, like maybe 6' with no distractions. As she gets proficient with a distance, increase the distance by a little. Don't rush. Make sure she is proficient at a distance before you increast the distance. Don't call her when you aren't sure she will come. Don't fuss at her for not coming. If she comes after a few minutes of calling, praise like she came instantly. Treats help when teaching. GRADUALLY wean her off the treats when she has become proficient at the desired distance. Always treat occasionally.
A fun game is for two people to start just a few feed apart and call her back and forth between you. Gradually increase the distance. If she figures out the game and starts going to the other person without being called then she gets no treats.
Good luck and keep us posted.