Here’s a fantastic video by Emily Larlham in her Dogmantic training series. She offers a complete selection of free positive reinforcement clicker training videos that are IMHO, priceless. Although the videos are targeted for dogs, simply insert the word horse when she says dog, and you’ll experience the same valuable results.
This particular video teaches what I think is an invaluable tool that I’ve used in a similar capacity with my horses if I see their attention begin to wander. For groundwork, I’ll make a type of kissy sound and then click/treat for eye contact with me, and under saddle, I click/treat for a flick of the ear in my direction, either from a voice cue, or a rein aid.
I love her explanation as to why a verbal no-no, or eh-eh, is ineffective.
Enjoy!
Cheryl
I Feel Good, My Horse Feels Good 
I am a huge fan of Emily’s and Pamela’s too and love their force-free apprach. I train boht my dogs and service dogs using this same approach and thout it would be possible with horses despite many people poohpoohing the idea.
Donna, Jessie & Lucy
http://www.youtube.com/use/supernaturalbc2008
http://www.youtube.com/use/supernaturalbc2009
How awesome you’re training service dogs force free. In training both my dogs and horses they seem to respond to this approach with similar enthusiasm and attentiveness. Each day I’m completely blown away the beauty of this type of training.
Thanks for the links!
Cheryl