Writing lessons on idioms, proverbs and such

Hi!
I am considering writing a collection about Italian idioms, proverbs, figurative expressions and so on, but I am not sure of how to structure it.
How would you write such lessons? Does anyone have any experience to share?
Thanks in advance for any feed-back,
Michele

Edited

Thanks for the ideas, but my question was rather about the form of the lessons, not about the content. :slight_smile:

I am not a big fan of learning idioms so I am not the best person to ask. However, I would be most interested in natural conversations, or even monologues on subjects of interest to the writer, where such expressions are used naturally. Since the dictionary may not provide the meaning for the idiom, you could provide a list of these expressions at the end, all in Italian of course, explaining what they mean and how they are used. You could either do this in the notes, or actually include it in the lesson with the audio.