There are lots of different ways to cast off. The method I show here is the one I first learned and I still think it’s the simplest to learn. But if you’re feeling more adventurous, YouTube is your friend on this one!
Just remember to pull the yarn through more than you usually would each time, to make every stitch nice and loose. Then the knitted fabric won’t bunch up – you want to avoid a cast off edge which is much narrower than the cast on edge.
Begin your row as usual. Knit 2 stitches. Pull through larger loops from your wrapped around yarn than you might normally do.
Then use the tip of your left hand needle to flip the first knitted stitch on the right needle, over the second stitch – yes, flip it up and over, and completely off the end of the right needle!
Knit another stitch. Flip your second stitch over your third and off the end of the needle.
Carry on doing this and you’ll start to see a nice straight end edge (‘cast off edge’) of the knitted fabric forming.
Continue doing this until you have just one stitch left. Stretch this stitch really wide, so it’s about the size of your fist. Take it off the needle, and pass the whole ball of yarn through the circle you’ve made. Pull on the yarn from the ball end, and close the circle.
Congratulations, you have cast off!