Of course, there’s never really anything ‘final’ about an exercise as complex as the canter pirouette! As the horse develops, the collection and tuning should get easier, but there will always be things to work on.
That said, there are a few ways to make the pirouettes really clean and crisp – and maximise those all-important double marks. Making the pirouette itself smaller and tighter is the obvious one, but it is very reliant on the horse’s development. Instead, it can be useful to think about making the entry and exit of the pirouette as smooth and clear as possible. Thinking shoulder-fore and showing a clear control over the collection both before and after the exercise can easily give the pirouette an extra half mark or more. Try riding on the centreline in shoulder-fore with half pirouettes at each end of the arena . You might be surprised how much you drift at the start and finish!
Another way to polish the pirouette is riding exercises that increase control over the stride length and turning. One way to do that is to ride transitions between walk and canter, while staying in a (large) pirouette. Initially, the horse will want to come out of the pirouette to achieve the transition, or make the first canter stride big and forward. With a bit of practice and tact, a careful rider can use this exercise to encourage smaller and more manoeuvrable steps.
Finally, as with all the movements, it’s important to find approaches and exercises that work for you and your horse – and that you enjoy. Don’t get into the habit of drilling the pirouettes; they are incredibly hard work for both horse and rider. Once the pirouette itself is established, adding the final polish is the work of a lifetime, and your approach may change over the course of weeks, months and years. Try to stay aware of strengths and weaknesses, and how they come and go, and don’t be afraid of tweaking exercises or introducing new ones as you and your horse change and develop.