When a newborn falls asleep, he or she falls first into a light sleep. If you wait 15-30 minutes (20 minutes is a good guess usually), your newborn will transition to deep sleep. A good test to see if your newborn is in a deep sleep is the floppy arm test. Pick up an arm and see how floppy it is when you gently let go. The arm of a newborn in light sleep is stiffer. The arm of a newborn in deep sleep is floppy. I used this on my daughter into toddlerhood on the occasions when she needed helping to sleep.
Once in deep sleep you can fairly easily transition even the lightest sleeping newborn. Now once that deep sleep phase ends and the newborn transitions back to light sleep, it might be game over. To handle the sleep cycle transition have you tried swaddling and incline sleep (a Fisher Price Rock 'n' Play, for example)?
Around 3-4 months infants fall into deep sleep first, usually over the course of 5-10 minutes. However along with this change comes many other changes to sleep and memory which can cause the process of "helping a child to fall asleep, then placing that child in a crib" to backfire for many kids.