What helped my horse a lot was riding a circle in the middle of the arena and made this smaller and bigger and then try to get your horse a little bit more collected when you ride the circle smaller. Try to do this with your seat and have a soft hand. When you ride the circle bigger again push the horse forward with the leg. Try to do as less as possible with your hand and bend the horse around your leg and keep the horse relaxed. Then you can start to ride transitions between trot and walk. Make sure you give the horse the rein when he needs it let him stretch a lot in all gaits. Another thing you can try is shoulder in on the circle, just about 3-4 meters and then ride forward out of the shoulder in and give the horse a little bit of the rein. I hope this can help you.
Hold light contact on your outside rein, while giving and taking softly on your inside rein. This will help them get into a frame as well as softening up. If your horses head goes to low, pick your hands straight up.
Legs before hands every time.
I sometimes find if horse is evading that giving something to think about helps. Lots of change of direction, circles, serpentine etc... get them focused... it's often easier in trot initially as well
You can do a “wiggle line” so get your horse moving because the key is energy!! And then do a few steps to the left, then a few straight ones on the rail and then to left. Also getting your horse to become rounder helps so play around with the bit good luck!!
Make sure that your horse is moving forward to start with, I have had awful trouble with this with my gelding however I have been abit lax with him as he is now refered to as the ‘only child’ on the yard. I would make sure that you ride forward and keep your hands in the correct position, high and together and that you are riding in a correct position. Then you must ride forward and your horse will come to soften as there is nowhere else for the energy to go.
Every horse is different, what worked best for my horse was using Vienna (lunging) reins before every ride. I would lounge him at all 3 gates having him make the circles smaller and bigger slowly. It will help strengthen your Horses hind end while helping round there back upwards and flexing into there pole while learning how to accept the bit.
I would do lots of circles and leg yield the horse in and out making the circles larger then smaller. Encourage using little squeezes on the inside rein and if they do soften relax the inside rein as a reward and use inside hand to pat. Ensure you have a steady rhythm and your horse shouldn’t speed up when you put your leg on to move them in or out of circle.
My dressage coach always says to "move the bit" from side to side. If the horse doesnt give in to the side to side action, take a little more rein with each movement. Once they soften and lower their head you can take a bit less, so that when they are soft and round you can simply move the bit by closing your fingers on your reins in an alternating rhythm. This way you maintain contact and conversation with their mouth, but you are not ASKING for more suppleness! Hope this helps