Common
Break a leg
Good luck
Barking up the wrong tree
To be mistaken, to be looking for solutions in the wrong place
Fit as a fiddle
In good health
Costs an arm and a leg
Very expensive
On the ball
Doing a good job
Raining cats and dogs
It is raining heavily
Bite off more than you can chew
Take on a project that you cannot finish
On cloud nine
Very happy
Do something at the drop of a hat
Do something without having planned beforehand
Pull someone's leg
To joke with someone
A dime a dozen
Something common
Break the ice
Make people feel more comfortable
Don't beat a dead horse
Move on, this subject is over
Don't put all your eggs in one basket
What you're doing is too risky
To get bent out of shape
To get upset
Beat around the bush
Avoid saying what you mean, usually because it is uncomfortable
By the skin of your teeth
Just barely
A storm in a teacup
A big fuss about a small problem
He has bigger fish to fry
He has bigger things to take care of than what we are talking about now
Under the weather
Sick
Bite the bullet
To get something over with because it is inevitable
Take it with a grain of salt
Don’t take it too seriously
Bolt from the blue
Something that happened without warning
Let the cat out of the bag
Give away a secret
Wrap your head around something
Understand something complicated