When I taught conversational English, one of the main things we had to be aware of was the use of idioms. English is full of them and you don't usually realize that, if taken literally, the language is either unintelligible or crazy.

As always, I blank on some of the most common ones I taught when I'm trying to think of an example. Here are a few that I'm able to spew out.

It's a jungle out there.
He's no Prince Charming.
Don't cry over spilt milk.
You're naked as a Jay bird.
She's guilty as the day is long.
Shooting fish in a barrel.

Try to be aware of what you say and hear even when not teaching so you can come up with examples. Then use that sketch paper BG suggested to draw out what it means.

Ferrick