In the first couple of months of life, a newborn generally feeds every 2 hours. If you are breastfeeding, offer up to 10-15 minutes on each breast; for formula feeding, offer about 2-3 ounces at each feeding. As your newborn gets older, she will tend to eat more at each feeding. If your infant produces 6 wet diapers a day and is gaining weight regularly, then she usually is getting enough food calories. Discuss your infant's feeding and growth with her pediatrician at each check-up.
Once your infant is between four and six months of age, she may start showing signs of readiness for solid foods. These signs include being able to support her own head, having good tongue thrust (can push food out of her mouth) and showing interest in the foods you are eating. When you feel your baby is ready and your pediatrician gives the go ahead, you can then start feeding her rice cereal, by mixing the cereal flakes with her breastmilk or formula. The familiar taste will help her accept the new food and rice cereal tends to be less allergy-provoking than some other foods.
Infants are just beginning new tastes and textures, so do not be surprised if she initially rejects your attempts. Be sure to try again in a few minutes. Once she gets used to the rice cereal, increase the quantity slowly. After rice cereal is accepted, you can then introduce oat or barley cereal followed by vegetables, fruit, and then finally meat. Introduce new foods one at a time in order to watch for any food allergies. Always wait a few days before introducing another new food. By doing so, you can watch for any diarrhea, bloating, rashes, or other signs or symptoms that may occur because of an allergic reaction to a food.
Soon enough you will be cleaning up pureed peas and carrots from the kitchen floor. In the meantime, enjoy breastfeeding or formula from a bottle until she is ready for solid foods.