This is the most important thing you can teach the babies. 

But all horses should do as well.

Something I learned from Mr. Coultor during a riding clinic in Nebraska was to always stop your horse and back him up two steps. 

My horse at the time was very heavy on his forward.  He just laid on my hands all the time.  So Mr. Coultor got on him that day and said to the 11 year old (me) standing in the center of the ring...always back him up two steps when you stop him. 

So what's this do?

Well for starters it backs him off your hand, so that he learns not to stop on the bit, but rather with his back end. 

But it teaches them more then that.  It squares them up, preparing them for their next transition.  Whether you're picking up your canter next or just walking away to relax and catch your breath, he is standing square, off the bit and off your hands, ready for what you request of him next.  Just makes him easier altogether.

Along those same lines is my next instruction...  

        Teach your horse to stop and stand on the rail.

Patience is key to riding and showing in an arena.  They need to be able to tolerate horses cantering by.  They need to learn to stand still and relax while they wait for your next move.  In the old days, the trainers would stop, drop they're reins and light up a cigarette.  We don't do that of course...especially if you don't smoke...but the horses learned to stand still that's for sure.

Lastly....don't congregate in the center of the arena...especially if you're on a young horse.  What does that teach them?  If they don't want to work, they head to the center.  Some horses you can never even take your outside rein off of them because they are so ring sour...they just dart to the middle every chance they get...lesson horses know this best! 

I was also taught to never dismount in the middle as well.  Unless there are a lot of people riding, I stop my horse on the rail...we stand relaxed, and then I slide off his side.  He is learning that we don't have to rush to the center of the ring to be done working for the day. 

There are exceptions of course.  If you are inside riding and a jumping lesson is going on then you can't stand on the rail the whole time and certainly not the best time to dismount.  But do yourself a favor....try to do these things on the rail as much as possible.  You'll be a happier rider, and have a less anxious horse for it.