In our case, we coached, and we cajoled, we scaffolded, we scolded, and finally-- we kept placing things under load...
that is, we kept DEMANDING that she use whatever EF she could bring to bear on things in her life.
I think, having worked with late adolescents, that this part of things is the key-- if you do it FOR them, then they may never really develop EF.
(And btw, in support of this hypothesis, I offer the well-known sequelae of special needs parents who "over" parent with the best of intentions, and wind up with adult children who CANNOT manage because they've learned helplessness).
When YOU have to figure it out, and there are consequences for not getting it right... well, that's when you start to use your brain to figure out work-arounds, to exercise those particular skills, reinforce what works, eliminate what doesn't, etc.
I like the two books below, also (in terms of discussing EF, particular detail within that domain, relative strengths and weaknesses, and planning for working with what you have):
Late, Lost, and Unprepared
and
Smart but Scattered
I found both to be helpful to me. The latter more than the former, at least for a NT child.
