Babies will do that on their own..to encourage them bring their favourite toy infront of them and.then slowly move it from right to left, left to right..

Hide yo self n Play some different sounds around him

Babies by birth have excellent listening skills but u can read this to have a focus on the mental development. Sing to ur baby and read to ur baby and u will see the difference soon.

He will do so on his own. Just buy some soft sound musical toys and rattles for the baby and play with him/