One of the most important things you can do for a horse?...show him where his "freedom" is. Show him there's a door always open, he just needs to look for it. Earnest Hemingway said it best, that freedom is learning to move freely with in your harness. That holds true for all of us, in all walks of life. Lets dial it back a bit, to good and/or encouraging training for horses.
It doesn't matter how old or how young, if I'm on the ground or in the saddle, if I'm using a hackamore or a bridle, or if I'm collecting the horse or not...I am ALWAYS working on showing the horse where the "free spot" is. Showing them where the free spot is, or where the open door is; calms a worried horse, encourages a trying horse, and motivates a dull or docile horse. If you can learn to soften and or open your hand at the right time, when the horse is coming your way, going through the open door you've shown him...I tell you, a whole other world will open up to you and the horse. The willingness of the horse to follow your lead will have no boundaries...no matter where you are going, whether its up the steepest hill, through the narrowest of spaces, or in the highest/fullest of collection or collected maneuver...because, if you do it right, when he gets there he knows he'll be free because you'll stop touching/stimulating/directing him with your hands, seat, or legs...and we all know, applying pressure stimulates the horse to move, and the horse learns what you want him to do when you STOP applying that pressure. It's just that some of us never stop with the pressure or stimulation, so the horse gets worried, gets dull, or just quits trying.
This is how I get my horse to be calm and willing, how I get him to trust me, so much so, that I could one day call on his heart and he'll give me everything he has...and run through fire or the proverbial brick wall because I need him to. Or, maybe he'll just be obedient and stop when I say stop, because the plastic bag blowing under his belly, terrifying though it may be to him, is far better than the oncoming truck he wants to jump in front of. This level of trust doesn't happen over night, and it doesn't magically happen...it takes a LOT of discipline to achieve, both on their part in training, and on our part in holding strong at the right times, and then softening, opening up our hands at the right time...and showing him where his "Freedom" is.