What are some key points to improve the collection of my horse?

Collection is one of the most misunderstood concepts in horsemanship because it's often described as something you do to the front end of the horse when it's actually something you build from the back end forward. A truly collected horse is not a horse whose head has been pulled into a vertical position — that's just a headset, and a headset without the corresponding engagement of the hindquarters is one of the most common false impressions of collection that exists in the western riding world. True collection is a whole-body posture where the horse's hindquarters are engaged and driving underneath his center of mass, his back is lifted and swinging, his poll is the highest point, and the energy from behind flows softly through a supple back and neck into a light, following contact with the bit. Start with forward. A horse cannot collect if he is not genuinely forward — meaning he is responsive to your leg, moving with energy and rhythm, and not requiring constant nagging to maintain the gait. Collection without forward is compression without power, and it produces a horse that is short-strided, tense, and uncomfortable to ride. Before you ever think about bringing a horse together, make sure he is freely forward off a light leg cue and maintaining his gait willingly. That forwardness is the raw material collection is built from. From there, work on suppleness through transitions and lateral work. A horse that is stiff through his back and ribcage cannot collect because he cannot swing and lift through his topline. Leg yields, shoulder-in, and frequent walk-trot-walk and trot-lope-trot transitions all develop the suppleness and responsiveness that collection requires. Think of these exercises as unlocking the horse's body so that when you eventually ask him to compress and carry, he has the physical ability to do so without tension or resistance. The actual collection asks you to contain the forward energy you have created rather than add more speed. Sit deep, close your leg to maintain impulsion, and softly close your hand to redirect that energy upward and back rather than letting it run out the front. The horse that has been correctly prepared will begin to shift his weight back, step under himself more deeply with his hind feet, and lighten his forehand in response. Release any time you feel him give, reward the effort, and build the duration gradually. Collection is a fitness achievement as much as a training one — the muscles required to carry weight on the hindquarters have to be developed over months of correct work, not demanded in a single session.