1. Feed Smart
To help your horse from being "amped up" by extra calories, balance his nutrition with the amount of exercise he gets. In particular, avoid giving him too many high energy carbohydrates. This may surprise you, but horses aren't designed to need grain. In their natural state, their only "grain" is the seed off the grasses they eat. So unless you're really working your horse hard or need one to gain weight, good-quality grass hay and a vitamin/mineral supplement are probably all he needs.
2. Turn Him Out
In the wild, horses move almost continuously. Keeping your horse cooped up in a stall is a great way to keep him edgy with excessive energy. If you can offer your horse 24/7 turnout, go for it. If that's not possible, try for at least 12 hours out of 24. If you're worried about your horses coat bleaching in the sun, turn him out at night. During hot weather horses enjoying grazing during the evenings when it has cooled down anyway.
3. Work Him Consistently
The more often and more consistently you work your horse, the more consistent your horse's performance will become. In a perfect world, you'd ride and/or do groundwork five - six days a week. If, like many people, you have just three or four days a week to ride, on the first day of the work period, concentrate primarily on things your horse already knows how to do well. Save most of the new learning for the following days.
4. Do Your Groundwork
It's the foundation for developing trust, respectfulness, and responsiveness. Groundwork establishes you as the "leader" by directing the movement of his feet. It also builds trust and communication and helps work off excess energy. The time you spend on groundwork invariably translates into a calmer, more focused mount.
5. "See" Like Your Horse
A horse's first response to perceived danger is flight. Keep this concept in mind as you're handling and riding him and you can avoid or at least anticipate many unsettling moments. Desensitization to stimuli that is frightening to your horse is possible and is well worth the time and energy spent. The reward is a horse that is safe and calm.
6. Give Him Something To Think About
Like a child looking to a parent, your horse looks to you for leadership. If you seem nervous when he starts to become unsettled, he'll assume there really is something to be afraid of!
So keep your breathing regular and your body language positive and relaxed. Whenever your horse feels tense under saddle, give him something specific to do. Instead of patting him (which inadvertently gives him no leadership to follow), put him to work and get his feet moving. Include circles and serpentines to get him to focus on what his feet are doing. Keep his mind busy until he settles into his work.
7. Making Deworming Easy
Take some molasses, honey, or apple sauce and put it in a syringe. Let your horse smell the sweet substance until he offers to take the syringe in his mouth, then squirt the sweet stuff into the horse's mouth. Do that for a couple of days until the horse begins to look for the syringe. Then take your dewormer and dip the tip in the sweet stuff. Give the horse the wormer. Then give him another syringe of the sweet stuff. Soon your horse will love that syringe just every now and then that sweet stuff seems to taste like dewormer.
8. Take Care Of Your Horse's Hooves
Pick out your horse's feet daily. This may sound pretty basic, but it's one of the best things you can do for his hooves. Your horse gets a head start on healthy hooves, and you get a chance to take early action on many common hoof problems such as thrush.
Each time you clean your horses hooves, take an extra couple of minutes after you've pried out any packed debris to gently clear the crevice of the frog and check for thrush, if needed treat the thrush with an anti-thrush treatment.