When you do yoga...your supposed to get tottally lost in it. Im a huge fan of it. DVDs and Books make your lose your concentration when your doing yoga and medating. I suggest you memorize some yoga positions, so when you do yoga you can be totally focused on listening to your body and relaxing.Look up some yoga positions on the internet, memorize them, then give yoga a go.
try: yoga.about.com
this site helped me...

