If you do something once in a blue moon...
You do it very rarely
If something is up in the air...
It is uncertain or unsure
If something is a no-brainer...
it is an easy decision
If something is a piece of cake...
It's very easy
If you beat around the bush...
You avoid talking about a difficult or embarrassing subject
If you go the extra mile...
You make a special effort to achieve something
If you blow smoke...
You exaggerate or say things that are untrue
If you face the music...
You accept the consequences of your mistakes or actions
If you sit tight...
You wait patiently
If you pull yourself together...
you calm down and behave normally
If you bite off more than you can chew...
You take on a task that is way too big
If something rings a bell...
It sounds familiar
If something is a far cry from something else...
It is very different
If something is a hot potato...
It is an issue which many people are talking about and which is usually disputed
If you cut to the chase...
You leave the unnecessary details and get to the point
If you cannot get your head around something...
You don't understand something
If you hit the sack...
You go to bed
If you see eye to eye with someone...
You agree on something with someone
If you hit the books...
You begin to study in a serious way
If you take something with a pinch of salt...
you don’t completely believe something
If you do something by the skin of your teeth
You do it by a very narrow margin, only just
If you cut corners ....
You do something in the easiest or most inexpensive way
If something is on your bucket list...
You want to do it before you die
If you rock...
You are great