First sign of a good latch is a comfortable, pain free latch. Sometimes it can be uncomfortable in the first 30 seconds, but after then should not be painful. You also want to make sure your baby’s chest and stomach rest against your body so that your baby’s head is straight. You want your baby’s chin to touch your breast and your baby’s mouth should open wide around the breast, not just the nipple. You should also see and hear baby swallowing. Seeing that baby is growing and satisfied is also indicative of a good latch.