There’s another one which is really good for socks or anything you want to have a stretchy edge on. It’s not very easy to explain but here goes:
slip knot as normal, make a diamond shaped “tent” around your thumb and index finger then the needle that has the slip knot on needs to catch hold of first the piece of yarn around the outside of your thumb, from the outside edge, then do the same with the yarn around your finger also from the outside edge. This SHOULD produce a loop type slip knot which you tighten as normal onto the needle and cast on like this til you have required number!
If that’s clearer than mud I will be very VERY happy!!