So to start, make a ring with the end of your yarn.
At this point, it may feel a bit flimsy and tangled and you might be thinking it's all gone wrong. You're probably absolutely fine. Carry on regardless, the next step will make it feel more sturdy.
Yarn over again
A bit better? It may still feel a bit odd. Hang in there. You now have a ring + 1 chain stitch.
Put your hook back through the ring and yarn over. It should look like there are two strands of yarn to the ring bit when you've gotten to the YO as below. This is important. You must always make your stitches around these two strands for the magic to work. You can just see it on the pic below - from the right hand side of the picture, on the hook there is the chain stitch, the two strands of the ring and the YO.
So, pick it up and yarn over
An hey presto! A double crochet (or a single crochet, if you're on t'other side o'pond).
Now it should be pretty straight forward. Continue working your stitches into the ring until you have as many as you need. Remember to keep the tail of the yarn alongside the ring and make your stitches around both bits, as though you're trying to hide the tail. I'm going to work 6 stitches into the ring...
And now for the magic...
The point of the magic ring is that you can get a nice tight centre.
So there you have it: six double (or single) crochet into a ring with a tight centre. To start your second round, work into the stitch marked with the red arrow. If you're following my tip from earlier this week about stitch markers, your scrap of yarn goes where the purple arrow is pointing.
This is a great way of starting amigurumi patterns, hats and granny squares! Like I said, life-changing!