Earlier quoted context omitted.
Talk about it. "That's great! Was it hard?"
This is great advice, but I'm not sure it hits the mark I'm trying to hit - I do already talk to my little guy about what things were hard vs. easy, and how much I admire his efforts, but there's a flow to interactions, especially with a small child - I'm looking for something I can use for a shorthand of this kind of conversation, because he totally loses interest if I just sit there and jabber for too long. If I wa…
In light of all this, though, how about "Great, you're getting better!" It acknowleges the accomplishment, marks them as improving over the past, and implies there's more to do? Again, projection. :)