idioms involving “letters”

Dot the I's and cross the T's

To pay close attention to the details

“Your financial projections will be published, so make sure you dot your I's and cross your T's.”

Mind your P's and Q's

To behave well

“The children had to mind their P's and Q's when their grandfather was in the house.”

ABC's

The basics

“The tutorial will teach you the ABC's of photo editing.”

A-list

Elite

“The top movie stars only attend A-list parties.”

From A to Z

From beginning to end, everything

“We discussed everything from A to Z so the meeting lasted until midnight.”

British usage:“From A to Zed”