Having the baby positioned properly at the breast is important in avoiding sore nipples and ensuring that baby is receiving adequate nutrition.
Be sure to:
1.-Find a comfortable position, sitting up or lying down.
2.-Baby's tummy should be facing your tummy.
3.-Support your breast with your hand, thumb on top and fingers underneath.
4.-Stimulate baby to arouse interest, tickling baby's lips with your finger or nipple.
5.-With baby's mouth wide open, quickly bring baby to your breast.

From:http://www.nursingmothers.org/tips.htm#po