When I first started crocheting I would tie my yarn in a knot around my hook, this lead to the knot either being way to tight on the first chain or it being all baggy after. I later discovered the magic ring, and simply could knot (te he) get the hang of it. Now I use a slip knot, I do suspect it it just another way to make a magic ring but I’ll tell you about it any way. These instructions are for working in the round.
1. hold your yarn in a loop
2. cross the yarn over/twist the loop with the tail end underneath
3. pull the tail end through the loop of yarn
4. pop you hook in the loop and pull the tail end to tighten the loop
5. Chain the appropriate amount for your pattern, I am going to make DO/TRC so I’ll chain 2
6. Work your next stitch in to the slip knot
7. Keep working in to the slip knot
8. Pull the tail end to tighten the loop.
I like this way for Amigurumi as, much like the magic loop is supposed to work, it lets you spread the stitches out a bit for the first row or two.
Using a slip knot working flat lets you tighten the first loop so it is neater at the end of the row.
Hope that was useful,