Every infant is an active learner. While it may seem that many of the actions your infant engages in during the day are random and spontaneous, the fact of the matter is that virtually every movement and sound has a purpose that contributes to her understanding of the world.
Through clinching, biting, grasping, turning, babbling and bubbling, your infant is experimenting with all the resources at her disposal--using her body and its immediate surroundings to find out how things work internally and externally. Your infant thinks, but thinks with her body.
Provide her with things she can grasp, roll around, push into, hit at, caress, and, in other ways, interact with. Talk and sing to her frequently and respond to her own babbling with appropriate noises of your own. The sound of your voice provides important modeling for future language acquisition.
Hold her frequently and play "pat a cake" and other fun games that help develop her sensory motor awareness. Provide her with a range of new experiences everyday. In this way, you'll be helping her do what she does naturally--actively learn about the nature of the world.