Safe sleep can be as easy as remembering ABC: Alone, Back, Crib. 
A - Alone
Babies should always sleep alone in a crib or bassinet. Sleeping with an adult, other child, or anything in their crib increases risk for suffocation and death. It is smart to sleep in the same room as your baby, but not the same bed.
B - Back
Babies should always be put to bed on their backs. Putting a baby to sleep on their side or stomach increases risk for Sudden Unexpected Infant Death. Once a baby is able to roll over on their own, then it is safe to let them sleep in other positions.
C - Crib
Babies should always be in their own empty crib or bassinet with a firm, flat sleeping surface. Instead of keeping a blanket in a crib, put the baby to bed in a sleep sack or one piece sleeper. Never out a baby to sleep in or on a swing, recliner, rocker, couch, adult bed, or soft mattress or surface.