Latch-on is the way a baby attaches to the breast. A good latch-on is important to:

"Remember babies breastfeed, they don't nipple feed"

Signs of Correct Nursing

Your baby's mouth is open wide with lips out.
His/her chin and nose are resting against the breast.
He/she has taken as much of the areola as possible into his/her mouth.
He/she is suckling rhythmically and deepley, in short bursts separated by pauses.
You can hear your baby swallowing regularly.
Your nipple is comfortable after the first few suckles.

Signs of Incorrect Nursing

Your baby's head is not in line with his/her body.
He/she is suckling on the nipple only, instead of suckling on the areola with the nipple far back in the her mouth.
He/she is suckling in a light, fluttery mannar rather than taking deep, regular sucks.
His/her cheeks are puckered inward or you hear clicking noises.
You don'r hear her swallow regularly after your milk production has increased.
You experience pain throughout the feed or have signs of nipple damage (such as cracking or bleeding)