To Step Up (one's) Game (used as a verb)

First Example:

Tina: Did you hear? I just got the project.

Alec: Really? I thought my proposal was a lock.

Tina: They liked mine better. Looks like you need to step up your game if you're gonna compete with me.

Alec: Don't get too cocky. You won one proposal, your first.

Tina: The first of many.

Alec: We'll see.

Meaning: To "step up (one's) game" is a phrase that means to improve one's skills or talents. This idiom is sometimes used in a somewhat joking manner between people who are competing, as Tina uses it above.  Alternatively, it can also be used to commend someone on their improvement, as in the next example:     

Vito: I heard you got a promotion?

Kate: Yeah, they liked my last couple reports and told me to keep up the good work.

Vito: Congratulations! You've really stepped up your game. I remember when you first got here, you seemed so lost.

Kate: I was lost! I was terrified someone would figure out at any moment that I had no idea what I was doing, and I'd get fired.

Vito: Well, you know what you're doing now. You'll probably end up being my boss one day.

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To Dig in (one's) Heels

Idiom: to dig in (one's) heels; used as a verb

First Example:

Jennifer: How is the wedding planning going?

James: Ugh.

Jennifer: That bad, huh? What's wrong now?

James: We can't agree on the music. I just want to have a DJ, but Natalie has dug in her heels on an expensive live band. She won't even consider any of the alternatives I suggested.

Jennifer: Just like she dug in her heels with that expensive hotel?

James: Yep, and I assumed she'll dig in her heels on some expensive flowers as well.

Jennifer: Well, it is her wedding day, so she wants it to be special.

James: It's my wedding day as well, and I don't want us spending the next ten years paying off loans!

Meaning: To "dig in (one's) heels" is a phrase that means to refuse to give in. This idiom is used when a person stubbornly refuses to change an opinion or action.  In the example, James says his fiancé Natalie is digging in her heels about wedding options that are too expensive.

Unusual for an English expression, the preposition in this idiom can be moved to the end without affecting the meaning. The expression to dig (one's) heels in (with the preposition at the end) is also correct and has the same meaning.

Here is an example of that usage:  

Michelle: How about sushi for dinner?

Greg: I don't want to go out. Can't we just order a pizza?   

Michelle: Well, I wanted something healthier than bread and cheese. How about that new salad place? That's not far?

Greg: Can't you get a salad from a pizza place?

Michelle: Not a good one. Let's go out.

Greg: There has to be a healthy delivery place. Let me look online.

Michelle: Wow, you're really digging your heels in on delivery, aren't you?

Greg: I just had a long day, and I'd rather stay home.

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