I'll tell you what made a big difference to me recently.
When you post to go up, push DOWN through your calves into your heels. The energy has to go somewhere, and you don't want to be 'kicking out' so really SINK your heels each time you post. I had to exaggerate this at first to help the muscle memory, but it's now more natural. Think with each UP, you must push DOWN.
Hope that helps too.