At one time it was believed that women should prepare their nipples for nursing by rubbing a rough towel on them from side to side or brushing them vigorously with a dry toothbrush. The good news is: Those days are long gone.
It is now recognized by La Leche Leage International that no preparation is necessary to avoid sore nipples. The best prevention for nipple soreness is correct positioning and latch-on of baby.
-Wait to latch until the baby's mouth is wide open
-Ensure your baby's mouth completely covers the nipple
-Check that your baby's lips are curled outward
-Ask a lactation specialist to observe the latch (forget modesty and discretion it will save you hours of pain for weeks to come)