A drop in the ocean

Stop acting the goat

It’s the last straw

On top of the world

He’s a dark horse

Belt up!

Beat around the bush

It’s raining cats & dogs

Pull your socks up!

Don’t judge a book by its cover

It cost an arm and a leg

On the ball

It’s a piece of cake

Miss the boat

Let the cat out of the bag

Let sleeping dogs lie

Hit the nail on the head

Jump on the bandwagon

Cut corners

Barking up the wrong tree

The ball’s in your court