We made two posters, brainstorming ideas of things he could tell Heavenly Father he is grateful for and then things he might ask for. One of us would come up with an idea and I'd try to draw a picture to represent the idea:
We've seen a great improvement in Isaac generating the words for his own prayers, although he still often wants help.
If I were to do this again, I'd draw some pictures as well as use cut out from old church magazines. (Especially pictures of Jesus, the prophet, etc.)
PS: Did you know that the Friend magazine has online activities? These have become a favorite Sunday activity at our house!