How do you teach manners?

I ask this because I am trying to teach P(18 months old) how to say "Thank You" whe I give her something...She has yet to say it...She says "MINE" to everything!! And it is so funny to hear her say it, especially to her sisters!!



This is such a sweet picture of P...I just had to share it here...See how nice and peaceful she looks?
I Like her this way :)