I believe that hard work, determination, and passion is what can create a better rider. I am also convinced that the skill and technique you are practicing can either create a happy horse or a resentful horse. My Aunt taught me that a happy horse will always try for you. She was actually talking about race horses but it is still about the horses mental and physical performance.
Learning to quietly communicate with your horse should be a huge priority. Sometimes you have to start over with the training. The horse may seem to resist, that is where skill comes in. As a rider, you owe it to your horse to understand what needs to be communicated, in the moment. This starts with a depth of understanding. Is the horse braced here? Is the horse coming from behind? Am I gymnastically benefiting this horse or am I using a technique that I actually do not understand the purpose of. Every horse is different in how they carry themselves and respond to their rider. It is up to you as the rider to develop an understanding of what is working and what is not. This takes time, and I personally believe the successful riders are the ones willing to take this time to look at the basics. Think about the training scale, apply it to your daily regime with your horse. Even when you are working on a movement like half pass...do I have rhythm, suppleness? The common problem I see is the way the horse will defend themselves. This can look like anything from tension to dysfunctional movements, behavior, etc. Remember, the horse looks for comfort but learns to defend themselves against pain.
When you are consistently getting low test scores with comments like " tense, braced, not staying connected in transitions" this doesn't mean the Judge does not like you or your horse, it is what you presented to them in that moment. Extensively study and perfect the movements that gave a low score. Even a comment like " ride your corners." Go home and set a cone in each corner of your arena until you can feel the correct bend through the corner.
Obviously riding is a partnership. Make sure you are training with someone who is very meticulous regarding your position and how you are able to communicate to your horse, keeping them balanced and correct. Do you want true training or shortcuts that will never hold up through the levels. Happy horses win medals!
“My horses are my friends, not my slaves” — Reiner Klimke