You will discover a wealth of wisdom when you get the answer to this question: "Don't they get it?"
Of all the things I have chosen to do in my life, by far the most challenging has been raising kids. I cannot tell you how many times I wished I had some super power like telepathy to convey a concept directly into their brains because words just weren't cutting it. The whole idea of taking the locus of control and bringing it inside (love that btw) is what I wanted to teach, and sometimes it gets lost in the "You could make this happen, why don't you?!" Your kids have to be confident enough to know that their failures aren't a reflection on their worth, but not so confident that they push the failure outside and into a place where they can deny an ability to change it.
Once it 'clicks' the world changes, before it clicks you're adrift in the white water rapids of life. Once you 'get it' you realize you don't have to stop the river you just have to exert the necessary force to navigate around the hazards, before that all you can think is that "nothing can stop this river, its going to kill me!"
Agreed. I have an eleven year old daughter, and I'm constantly quoting the movie version of Alfred Pennyworth to her, in the perennial hope that some day it will just click.
"And why do we fall Master Bruce?"
"So we can learn to pick ourselves up."
I like to think that I've done well, letting her get into programs that she finds worthwhile, hoping that she'll apply herself in a way I never did at her age. It's painful watching children fall in and out of like with things when they realize how much work is involved, but having given her exposure to enough things, I've found that when she can grasp onto the kernel of something she truly enjoys, it's a lot easier for her to overlook the effort involved.
It doesn't fix the fact that some things aren't worth trying for (especially eating her Spinach, though that one's obviously not crucial), but then you have to overlook that y'know, she's eleven, and if I'm honest with myself, she's a million times better at applying herself than I ever was at her age.
The only thing I've found that works is when there are crises, we try to collectively break down the problem into its smallest component parts, and deal with them in very small chunks. Another very useful tool has been the "Destination Imagination" program -- I don't know how old your kids are, or whether the program is available in your school district, but it is, specifically, an unstructured lesson in getting kids to learn creative problem solving through small, focused problems that they are challenged to solve (like how to most efficiently roll golf balls into a bucket on the other side of the room using a broom, two chairs, a pack of bendy straws, etc.)
Having been a judge for DI, I can assure you that the children came up with a variety of solutions I never would have fathomed, to varying (but often impressive) degrees of success.
I've always tried to give my kids as many different experiences as I can, when they were young I tried to set things up so that we could fail together at things, and then work through them. It was important that they learn that failure is a way to learn how to not fail. Ignorance is just a signal that there is something else to learn. Pain is nature's way of saying "Hey, reconsider carefully what you are doing or just did."
But every kid is different, so the only advice I can really give is this; Understand that your kids are learning all the time, be mindful and deliberate in your interactions.