By the time she's about 6 months old though sometimes it takes a little longer, your baby's hand control is developed enough that she can rake a small object toward herself. She may not actually grab it, but she can bring it to her. You can help your baby practice this by placing a toy within her reach and waiting for her bring it close. In another month or so, she'll learn to grab larger toys and start to practice moving objects from one hand to the other. Let her work with this skill by giving her a small rattle or toy to hold on to. Then help her transfer it to her other hand. Then move it back to the original hand, and so on. When she learns to transfer objects, a whole new world opens up she now has two hands to have fun with!
Your baby now sees and hears the world almost as well as you do. Her communication skills are expanding rapidly, too, as evidenced by her squeals, bubbling sounds, and operatic octave changes. Her sounds can demonstrate her attitude or response to objects.
At this age, about half of babies babble, you can encourage your baby by babbling right back at her and by making a game of it, your baby will appreciate your encouraging her by keeping the conversation going. She'll also appreciate it if you listen as if you understand everything she says and find it extremely interesting. Try simulating a conversation: You listen while she talks, then ask a question and wait for a response!