The World Health Organisation and other health authorities usually recommend exclusive breastfeeding for the first six-months, without supplementing with cereal or juice etc.
Aside from that, there are no hard and fast rules as to what you should start with after 6 months.
It will depend on baby's appetite, whether he has teeth and how ‘by the book’ you are as a mum.
Cultural factors also play a role. Children in Asia usually start with rice and rice water. Their western counterparts usually start with a cereal based diet.
According to nutritionists, infants should be weaned slowly and gradually by introducing one food at a time. However, there's nothing wrong with introducing your child to a variety of different tastes over time. In fact some studies show that children introduced to a wider palate early in life tend to have healthier diets in the long run.
You should, however, be aware that there are some foods to avoid when weaning to avoid allergies and choking in infants.