I recommend the "English Idioms in Use" series by Cambridge. Your Q is too general for us to give a good answer. If you have a specific situation you want to ask about, you will probably get some interesting responses.

Try this: https://www.chapter-living.com/blog/28-classic-british-idioms

We use it so often we dont even remember it's an idiom. XD Speak of the devil Again and again Hang in there Call it a day A blessing in disguise So far so good