to preach to the choir (or the converted) to try to persuade people to accept opinions and beliefs that they already have, and that they do not need to know

(right) on the money – correct; accurate
His prediction was right on the money.

carrot and stick

Exams are part of a carrot and stick method.

meaning: there are obviously no real carrots and sticks involved. The image is that of a donkey being encouraged to move forward by dangling a carrot in front of it or by hitting it with a stick. We can use this idiom to describe any event that involves more abstract rewards (the carrot) and threats (the stick).

**** AGREE TO DISAGREE

Narazila jsem na toto a pokud někdo objasní význam, budu vděčná.

****

shodnout se na tom, ze se neshodnou

We agreed to disagree – shodli jsme se na tom, ze se neshodneme.

Thank you very much.

Have to hand it to sb – inf, used to say that sb deserves praise for sth

He cheated on me and broke my heart. But I have to hand it to him, he was honest and told me straight.

sheltered life/childhood etc. – to live a life while being protected from the unpleasant aspects of life

He's lived a sheltered life and that's why he's so crushed now.

have a frog in your throat informal
- to have difficulty in speaking, especially because of a sore throat

A: „I'm sorry. Do you think you could do the presentation for me? I've got a frog in my throat, and I don't think it's going to clear anytime soon.“
B: „Yeah. You sound kinda froggy. Try drinking some hot lemon tea.“

the real McCoy (informal) – a genuine and real thing

I just bought a new Rolex watch. Mind you, it is not one of those Chinese fakes; it is the real McCoy.

Vote with one's feet – to express one's dissatis­faction with something by leaving, especially by walking away.

to scare the shit out of sb- means that you scared sb a lot…
Goddammit! You scared the shit out of me! I shit my pants 

That is an interesting idiom, recently I have heard it in a podcast which I once downloaded in Mp3 format.
So here is another idiom that I found in one article on VOA Learning English website:

Pan out- to happen or be successful.

up the duff – pregnant, usually unplanned (AusE, BrE – slang)

So all of a sudden, she has no job, no place to live, she's up the duff and she's back on your doorstep…

suck up – to behave obsequiously
tee off – to begin, start (informal)