feet on the ground

"He has kept his feet on the ground and it is only the start for him."

I don't know, but you have to keep both feet on the ground.

Instead he was home after a doctor's appointment and it was only by chance that he spotted a pair of feet on the ground in his back garden.

And so I try to keep my feet on the ground.

"It's happened quickly but I'm going to keep my feet on the ground and work harder and harder."