Newborns sleep up to 16 hours a day, often in stretches of 3-4 hours. Until the newborns completely adjust to life outside the mother's womb, they do not know the difference between day and night which often means sleepless nights for the parents. Baby's stimulation ( talking to, playing with, etc) should be minimized at the night time so the day/night routine is quickly established.
Trying to keep the baby awake during the day time does not help with increasing the probability of better sleep during the night. Remember that you can not spoil the baby by holding him/her too much.
While sleeping, babies should be on their back and not on their stomach. This is because of an association found with babies sleeping on the stomach and a serious condition called Sudden Infant Death Syndrome (SIDS).
Additional advice regarding baby's sleep is available in the 'sleep tips' section.