Learning to sleep on his own

There has been some improvement in Lucas's sleeping habit in the last two days. We used to lay down with him and wait until he falls asleep before we leave the room. In the last two days, I will tell him

Me: Lucas, Mommy is hungry. Mommy is going to 'mum mum' (eat). Lucas goes to sleep, okay.
Lucas: NO
Me: Mommy is hungry. Mommy is going to 'mum mum' (eat). Lucas goes to sleep, okay.
Lucas: (reluctantly say) bye bye. (and give his kissess)

I did the same thing again the next day and he buys it.
Dominic tried it too and it works.
So, we are consciouly telling ourselves to train him to fall asleep on his own.
And we are keeping our finger crossed.