Encountering Grover in long range open spaces - don't PEEK around the corner.
Good Grover players throw axes preemptively and you can take a lot of damage. Use short sprints between cover. This way it's harder to predict where to aim.
Try to take out ling range targets like kinessa. And try to predict the position of fast moving champions.
Be the last one down by timing your heals so that your team can regroup around you even if you die by then