If you want to make larger jewelry pieces using crochet, then the double crochet stitch is good to know. Like single crochet, you need to start with a base row of some kind, such as either the a crochet chain or you can do this after doing single crochet (as shown in this tutorial) so you can get more practice in between different stitches.

In the pictures used for this tutorial, I'm using a size "I" hook (5.5mm), and the yarn is Worsted medium.

For more information about crochet, see About.com's Crochet site.