Best Answer - Chosen by Voters
When you ask for the canter, it's largely the same as asking for the trot. You squeeze with your legs or kick if you need to. When you ask for the canter, instead of clucking like you do when you ask for the trot, you should make a kissing sound. Also, to make sure the horse picks up the correct lead, you should move your outside leg back so it's behind the girth, leave the inside leg at the girth, then squeeze. It's also helpful if your horse is going around a corner when you ask for the canter... that helps them get the correct lead.
Don't worry, when it's time for you to canter, your riding instructor will help you... she'll tell you what you should do to the horse and when. And your instructor is not going to let you get hurt, so don't worry about anything when you're on a horse... be confident!