Here's a final photo showing the swatch after a few more rows have been completed. Notice how the fabric is curling up a bit. This curling is perfectly normal with afghan stitch; that's just one of the characteristics of this type of fabric.
When I use afghan stitch in my crochet projects, I try to find clever ways of counteracting the curl. In some cases, joining two pieces together back-to-back will do the trick; see these potholders and this purse for examples. In other cases, adding a substantial edging is enough to counteract the curl. The edging doesn't have to be fancy; it can even be a wide band of plain single crochet. See this dishcloth for an example.
Those of you who began this tutorial by crocheting 30 stitches, remember to visit this page to get the rest of the instructions for crocheting your potholder.
More Free Afghan Stitch Patterns:
To see more free crochet patterns featuring afghan stitch and Tunisian crochet, please be sure to stop by my page of free Tunisian crochet patterns.References:
For references and additional reading on the topic of Tunisian crochet, see this page.