Begin with a foundation to add your stitches into.We made a slip knot and chains here, but you can also create a magic circle.
Hold the working yarn in your non-dominant hand and use your finger and thumb to hold the chains close to the hook.Wrap the working yarn around your hook, going counter-clockwise around the hook.This is called a "yarn over".
Insert your hook into the chain or stitch you'd like the double crochet stitch to be in.(Generally with a double crochet you'll insert your stitch into the 4th chain from the hook to keep your rows straight.)You can also work a double crochet into a magic circle or a stitch from the previous row.
Yarn over. (Wrap the working yarn around your hook in a clockwise direction.)
Guide the top part of your hook back through the same chain.
You should now have 3 loops on your hook.
Yarn over again.
Pull your hook with the working yarn through the first 2 loops on your hook.You should end up with 2 loops on your hook.
Yarn over one last time.
Pull your hook and the working yarn though the 2 loops on your hook.This will leave 1 loop on your hook, the starting point of your next stitch.Your double crochet stitch is complete!