damage control: to fix a problem, usually used with the verb "do."

Clint made his girlfriend angry because of something he said, so now he has to do damage control.

damaged goods: a person who has gone through a difficult experience; this can also be used for a thing that is broken.

After her boyfriend broke up with her, Monique feels like she’s damaged goods.

(one’s) days are numbered: to have a sickness that will result in death; to be at the end of a period of time.

Due to an aggressive form of lung cancer, Geraldo knows that his days are numbered.

dead as a doornail: dead

That fish washed up on the shore is dead as a doornail.

deal me in: make me a part of an agreement; I agree.

I like your ideas and I want to be a part of this. Deal me in.

(not) deal with a full deck: to be crazy.

It’s obvious that Tara isn’t dealing with a full deck these day. Look at what she’s done to herself.

die with one’s boots on: to die while working at one’s job; to die in the line of duty.

I don’t plan to die with my boots on. Hopefully, I can retire before I’m 60.

(as) different as night and day: to be very different; one person is the opposite of another.

Although they’re brothers, they’re as different as night and day.

do it blindfolded: to know something so well, one can perform the action without looking; to be very familiar with an action.

I’ve biked to work so many times over the years, I could probably do it blindfolded.*

*blindfold: a cloth or something similar that prevents sight.

do the legwork: to do all the necessary preparation work for something: making phone calls, making arrangements, researching, and traveling.

Michael will have to do a lot of legwork to prepare for his business meeting.

do unto others as you would have them do unto you: treat other people the way you want to be treated; also known as "the golden rule," this comes straight from the Bible.

Jesus advised that people live by the golden rule: "Do unto others as you would have them do unto you." 

do your own thing: do something that you enjoy doing

Instead of going out on a Friday night, George likes to do his own thing and play the cello.

don’t hold your breath: to say that something is going to take a long time.

A: When is Luke going to get a regular job?

B: Don’t hold your breath. He’s happy working just 20 hours a week delivering pizza.

dose of one’s own medicine: to receive punishment or treatment that was previously given to others.

Christine got a dose of her own medicine when her boyfriend, Tom, ignored her at the party.

down to the wire: close to a deadline; at the very end of a time period, something is finished.

It’s down to the wire. We have to get these documents signed and delivered by tomorrow.

drag one’s feet: to take a long time to do something; to be reluctant to act.

Victoria knows that Ted wants to marry her, but he’s really dragging his feet in deciding when to do it.

drive a hard bargain: to negotiate skillfully and get what one wants.

Although Scott Perkins drives a hard bargain, he’s tries to be fair to the people he does business with.

drive someone crazy: to make someone crazy; to cause worry.

The daily pressure from his job is starting to drive him crazy.

drop in the bucket: a very small amount within a large amount.

Tanya made another payment on her loan, but she owes so much money, the check she wrote was just a drop in the bucket.

drop the ball: to make a mistake. This is a sports metaphor, probably taken from football.

A: Your score on that test was terrible. What happened?

B: I don’t know. I really dropped the ball, didn’t I?

drunk as a skunk: very drunk; someone who has had too much alcohol.

Look at Henry! He can’t drive home. He’s drunk as a skunk.