To produce a good strike off, your horse must be prepared with little half halt checks to bring the hind leg more under his body so that he can ‘jump’ into canter .At the same time he should be flexed a little to the strike off side.

Put the inside leg on the girth.

Use the inside rein with a ‘taking and giving’ feel for flexion.

Use the outside rein to control how much flexion you need and steadies the outside foreleg
.
The outside leg goes behind the girth to hold the quarters.

Your seat bone weight should be forward on the inside with the hip up.

As you press the ‘inside button’ with your inside leg, allow your horse to flow into canter with a softening on the inside hand.

In the canter the rider keeps the hands steady and makes half halts to maintain the bounce in the stride and sits softly still and upright in the body.
Remember to always ask your horse the same way each strike off so he understands immediately what you mean. It also set the ground work for your flying changes.