We have always make it a habit for him to 'say' his prayers first every time before he have his meals. When we first started Ben on solids (he was 6 mths old then), I will cup his hands together and say his prayers for him.
But when he turns 1 year old, I tried one day asking him how he prays and he clasps his hands together and looked at me... awesome... And one time, when my MIL was having her dinner, Ben looked at her and clasped his hands and she stopped and quickly said her grace and then Ben continues playing his toys... :D
Anyway, enjoy! :D