Instructions
Save your game immediately before the battle with Crying Wolf. This will allow you to play the battle from its entirety if you need a break. Exit the game.
Load the save data. The batteries for Snake's night vision goggles will be fully charged for the battle.
Turn on your night vision goggles and equip the SVD or sniper rifle in your inventory. Crying Wolf is elusive and night vision combined with the sniper rifle will provide for accurate shooting.
Find a place you where you are comfortable, and that allows you to use your sniper rifle. You should stay in this general area during the whole battle, because Crying Wolf jumps around so much that it is impossible to run her down. Just wait for her to come into sight.
Aim for Crying Wolf's head. About one quarter of her psyche bar will be lost if she is shot in the head.
Attack her as she runs at you with a rifle or RPG-7. She will run away after her attempt. Follow her footsteps with the night vision goggles. Shoot her with any weapon.