I had never heard of C2C crochet till a few short weeks ago. When I finally went to learn it, it turned out easier than I thought. 
Below is an easy YouTube C2C tutorial for beginners by Moogley for LionBrandYarn.
* C2C crochet is Corner to Corner crochet. And yes, the work is indeed worked diagonally from one corner to the other.
This video shows the basic and most common form of the C2C crochet. However I prefer my Linked C2C crochet because that yields a no-hole C2C fabric. The basic C2C has a lot of “holes” … which is not always the preferred crochet fabric especially if you are making winter blankets!
If you prefer written instructions, have a look at How to Corner to Corner Crochet (C2C) for Beginners (by makeanddocrew.com)
[…] talked about the Basic and most common form of C2C crochet before. But my preferred C2C crochet is this Linked C2C crochet. I have currently not as yet […]