My previous problem with putting my son to sleep at night is kind of solved now. Now I don't need to carry him or rock him or sing to him when I want him to sleep (I did all these in the last 9 months and my son is now 10 months old.) What I do now, for your reference, are:-
(1) half an hour before his usual bedtime, 9pm, I set the light in the living room dim, play some light music and STOP playing with him completely. Sometimes if he is in the mood I will read a book with him (but most of the time he is too impatient with sitting down with me to read a book!)
(2) at 9pm, I take him to the bedroom and turn off all the light, shut the door then put him into his own cot, in which he plays by himself for about 10~20 minutes, i.e. pulling up, jumping up and down, rolling over, babbling, etc. until I guess he makes himself tired. I sat on my own bed (his cot is next to our bed) and don't make a sound.
(3) Then when he's ready for sleep he will stretch his arms wanting to be carried. Then I take him to my bed and kiss him goodnight and he will roll over for another 5~10 minutes and then fall into sleep.
As I said, since his birth I carried him and rocked and sang him to sleep and I never really tried to let him sleep by himself. In other word I didn't make this change purposely. What happened was: one evening he suddenly refused to be carried by me and struggled to go into his cot... after the third night I realised he wanted to play a bit in his own cot then roll a bit in my bed then sleep. Just happened so naturally~~~~
My son normally sleeps through the night but he sometimes, once a week on average may wake up in the middle of night crying with tears, or simply cry in sleep. I would lift him up and cuddle him back into sleep. I don't know the reason. As it doesn't happen often so I never try to find out why...