Introducing the Canter and Fill
When teaching a horse to jump, it is super important that you do not let them cut their corners or change their speed. Anytime they make a mistake, instead of continuing around the course, take them back and correct the issue. If they cut the corner, show them where they should have gone. If they change their speed do a downward transition (if they were getting too quick) until they can find relaxation, or do an upward transition (if they were getting too slow) to encourage them to stay in front of the leg.