In this example, I'm going to show you how to make a magic circle with 10 single crochets. Normally, you'll see it used with single crochet, double crochet and half-double crochet.
First, you make a circle by putting the yarn tail behind the working yarn (coming out of the skein). At first, until you master this technique, you'll want to leave a longer tail, probably 5"-6". Once you have it down, you'll be able to shorten that length.
Next, use your hook to pull a loop through the circle.
Now you begin your single crochets. The hook goes through the circle (as in the first photo), you pull your loop up around the circle and the tail, and make your single crochet.
Continue crocheting until you have the required number of stitches. Be sure that each stitch goes around the circle and the yarn tail.
Now, I realize that I didn't take this picture correctly! What you need to do at this point is remove your hook and make the loop from the hook bigger, just so that it doesn't pull out. Then you're going to hold the circle in one hand and gently, but firmly, pull on the tail until the circle tightens...
...and looks like this! Insert hook back into loop and continue crocheting. Do be careful when tightening the circle as some yarns, such as handspun and rovings, can break fairly easily. I even had cotton yarn break once.
You will need to fasten off the tail so that it doesn't pull out; you can do that after you crochet a couple of rounds, or like me, just wait until you finish and do all of the fastening off at the same time.
If it's awkward at first...no, check that. It probably will be awkward at first, but I encourage you to practice, and I think in no time at all, you'll wonder how you ever crocheted round stuff without the magic circle!