Hi, I've practiced signing with my son since he was 6 month old.
Didn't buy any books or DVD. Just check out youtube for video of Firesse.She's super cute and her mom teaches her all kinds of signs.
From there, I taught my son to sign 'more' (first sign

), good, no, no more, food, water, milk, light, phone, etc.
He signed back at 6 months(esp with food for encouragement,haha)
You can try some sound effects and motionese. really helps
All the best
