How to do Corner to corner (C2C) crochet – video tutorial
If you don't have experience with the C2C technique, you can find instructions on my blog.
Corner to corner crochet (c2c) is a technique that works just as it sounds – you crochet little squares at a diagonal from corner to corner, and increase each row by one square until your project is tall and wide enough, at which point you start decreasing each row.
Almost all corner to corner crochet projects are based on a square or rectangle design. So learning how to crochet a C2C rectangle (or square!) is pretty much the most foundational skill you need to master. You can find the c2c rectangle video tutorial here: https://bestofcrochetpatterns.com/how-to-do-corner-to-corner-c2c-crochet-video-tutorial/