My son is a year a half old. He has never been a great sleeper. Lately My wife or I have to settle him into his crib, turn the lights out and then stand beside the crib and encourage him for a while(some nights longer than others). When he seems like he's going under we retreat to a rocking chair on the other side of the room. At this point we don't say anything, just sit quietly and let him work it out until hes asleep. If he gets restless at this point we'll just say "Shhhh" quietly a few times, so he knows were still there.
A few nights ago I run through this process and I'm sitting in the chair. It's been a tough battle tonight and I've had a long day, so after Shushing him a few times he goes quiet. Victory. I relax lean my head back in the rocking chair and close my eyes. As I'm about to get up and make my escape I hear from the closet about a foot from where I'm sitting "Shhhh"
There's a night-light in there now. I told my wife I think it may be calming for him, but its completely for me.