“Have bigger fish to fry”

“Against all odds”

Despite very low chances of success.

“Brush up on something”

To improve knowledge or skill by reviewing it.

“Blow your own trumpet”

To talk proudly about your own achievements.

“Bottom line”

The most important point or final result.

“A storm in a teacup”

A lot of anger or worry about something unimportant.

“Butter someone up”

To praise someone too much in order to get something.

“Break even”

To make neither profit nor loss.

“A shot in the dark”

A guess made without much information.