“Rome wasn’t built in a day”

“Cast in stone”

Fixed and impossible to change.

“Be in over your head”

To be involved in something too difficult for you.

“Big fish in a small pond”

An important person in a small group or limited environment.

“In full swing”

Happening with full activity and energy.

“Go down in flames”

To fail completely and dramatically.

“Carry the day”

To win or succeed.

“A storm in a teacup”

A lot of anger or worry about something unimportant.

“Go in circles”

To make no progress while repeating the same ideas or actions.