Find where her illusions are and use that to your advantage. If someone targets her, she will likely try to teleport away and confuse you. Surprise her by having someone else near her spot or quickly running after her while staying away from enemies
Dimensional Link can also let her travel to the last active illusion spot after it dies, and this can help her escape combat quickly, especially if she has an illusion hidden to heal her team. She is only able to have 2 active, so know their spots!
Ying's Ultimate ability, Illusory Rift, heals but can let her use her Dimensional Link to teleport to her team. If Ying uses this right after respawning, look out for her teleporting to her team and kill her to waste the Ultimate.