Teaching hand signals is a great way to improve communication with your dog. These are the hand signals that I use with Ryka, my Belgian Malinois puppy who is 5 months old. We started training with hand commands first and I find it has been the most effective way to communicate with Ryka.
Sit/Sitz - fist
Down/Platz - flat hand, palm down
Heel/Fuss - Fist on the side
Middle/Mitte - Fist in front of body
Around (to other side) - Hand around the back