keep (one's) feet on the ground
To be and remain in a calm, stable, sensible, and pragmatic state or condition; to not be subject to extreme emotional reactions. My father has always been a rock of level-headed judgment and advice. Even during our family's lowest points, he's always kept his feet on the ground.
keep one's feet on the ground
and have one's feet on the groundFig. to remain calm and stable. You will do all right if you have your feet on the ground. Don't get carried away. Just keep your feet on the ground and you will do fine.