"You had better," or "You'd better," means that you should do whatever it is. This phrase is used to coerce or urge someone. "You'd better do your homework," is one example. The unspoken part of this phrase is that if you don't do whatever it is, you will be punished, or will get an unwelcome consequence.
Remain confident, do not worry, things will go better tomorrow.
RFP is not an idiom. It's an abbreviation.
It's not really an idiom. It means "what are you thinking about."
It is not an idiom, it means your nose is itching.
idiom means expression like a page in a book
It's not an idiom. It means the tip of your nostril.
"Sieve" is not an idiom. See the related link.
If used as an idiom, it usually means that you are confused about something. The image is of you scratching your head to try to think better.
This is not an idiom. It is a measurement. $100,000 is how you write it in numbers.
Simply its mean a bully.
The idiom your blood is boiling usually means that you are mad/furious.
It's not an idiom, and it's "A picture paints 1,000 words." It means that showing is better than telling, that actions speak louder than words, that the way you act shows your true intentions better than the things you say you'll do.