Have you been practicing your single/doubles depending on what you like to call them? And you have progressed to the next stitch?
EDIT: My stitch tutorials work into the back loop. For more information check out this post
So here we have the US Double Stitch and the UK Treble. Sometimes I call it Triple, just to confuse the issue some more. Abbreviated as dc or tr. First make a foundation chain. Any length will do to practice.
you may like to use a pin to mark the chain.
This is just like how you have been doing the single/double crochet, but you do it twice!
Turning Chain counts as first stitch of next row.
Woo Hoo! That is the next stitch! I have done a bit less commentary this time, so please ask away if something doesn't make sense.
I would say this is the most common stitch you will use.