The Senses
7 months+
Touch At aroud seven months your baby starts to explore through touch. Toys that respond to your baby's manipulations, such as pull toys, rattles and soft toys can encourage this.
Sight At around 7 months your baby will start to get more interested in visual aids. This can be encouraged by reading baby books and popup books and maybe interacting with your baby through a hand puppet.
10 months+
Sound At around 10 months your baby will begin to become more receptive to sound. If your baby hears sounds such as the phone or door bell you should show them where the sound comes from. At this stage babies enjoy musical toys that respond to their actions.
1 years+
Smell At around 11 months your babies sense of smell will begin to develop. You should help your baby explore smells and as bizare as it may seem, letting them smell and see an item such as a lemon will encourage development in this area.
(Taste: Newborn babies have a well developed sense of taste and some people believe this peaks at around twelve months. At this stage, you should be introducing your baby to a wide variety of tastes, experimenting with flavours and trying to discover their likes and dislikes.)