It's a given that horses, especially at the start of the season, get to a show, and seem to forget about 50% of what they learned over the winter. They're "high". They're excited to be "out & about" and are overwhelmed with the need to see and hear everything, and "talk" to everyone.
Nothing can be more frustrating than to take your ordinarily "tame" horse to a show and have them become a screaming, prancing, ninny that stomps on your feet, breaks your equipment, knocks into you and generally embarrases you at every turn. That'll take the fun out of horse showing, lickity-split.
What can you do? A horse is a horse, of course, of course- right? Well, yes, and no. There IS plenty you can do to help insure that your horse is a well behaved, enjoyable, horse show companion. No, it does not involve sticks, carrots, or talking with a "down-under" accent. It does involve a lot of common sense and firm consistency.
In other words... dealing with horses (like raising young children) is the last of the benign dictatorships. It really is- BECAUSE I SAID SO, and ITS FOR YOUR OWN GOOD. What this means- you ask nicely, but accept nothing but compliance. You make the right things easy, and the wrong things hard (or uncomfortable) for your horse. You're setting them up for success, and conditioning them to behave under all circumstances.
In the majority, problems experienced with horses showing stem from a certain degree of barn-sourness. Speeding up- the second direction, going toward the gate (flat and jumping..
When Schooling: 1) School downward transitions going TOWARD home, and upwards going AWAY. 2) Dismount in an area well away from the gate. Preferably a "scarey" area. Make that area a "good" spot. After all, what's NOT good about getting done working?
Change the Location of "Happy-Land". Your horse gets fed, watered, and gets to rest in their stall. Why wouldn't they want to get back there ASAP? Really, horses aren't the dumb animals we accuse them of being. So.. since you can't feed your horse in the middle of the arena (okay, okay.. at home, maybe you can), and you need to take your horse out of their stall to work (yuck!) them, what CAN you do? Make "home" a little bit less appealing by not providing them with instant gratification when they return to it. I.E.- don't immediately remove their saddle. Leave them a bit uncomfortable for 30 minutes or so. Tie them up. Again, it's about them not being made super comfortable the moment they get back to their stall. Tie them in their stall- remove a little bit of their liberty. (remember, if you're tying for any length of time, tie where they can reach their water) BONUS- this teaches your horse patience. Think about it. What horses are the most patient and well behaved? Roping horses. Ranch horses. Horses that have to spend large chunks of their day standing tied. It's not mean. It's simply becomes a way of life. Doing these things when you return your horse to their stall isn't about making their stall a miserable space, it's about changing the association with returning to their stall and good things happening. Good things still happen there, just not immediately.
Take your time returning. When you DO finish up, and are returning your horse to their stall (paddock, or whatever) dismount and lead them (firstly, this never allows them to think that they can take (carry) you back to the barn) very slowly. This is very, very simple. It re-enforces the "DO NOT rush back to the barn" mentality that the other steps help instill. It also helps to break the link in your horse's mind with ending work and returning to "happy-land".
These things take virtually no time or effort on your part- only awareness. And they work. How can you beat that?