Give (I'm giving to you) is signed by holding your thumb to all your fingers together on your dominant hand, and moving your hand away from your body. The motion looks like you are giving the listener something. Some people also sign give with both their hands moving simultaneously in the same direction.
By changing the direction of the motion you can indicate, "Give to me," or, "He is giving to her."
Usage: You can make a game of giving an item back and forth, signing along with give. This starts to get your baby used to the idea of giving and receiving something. It will also start to get them comfortable with the idea of sharing, that they can give someone else an item and not permanently lose it.
We like to teach this sign to instill a culture of generosity and sharing.