Try free lunging and liberty it is good
I would just try and be with him as much as possible and as many other pwople have said, grooming your horse and reading to him help alot.
There are a few things you can do to improve the relationship and bond you have with your horse.
- Grooming with brushes in his stable.
- Massaging your horse with your hands.
- Reading to your horse.
- Speaking with your horse.
- Clicker training.
Grooming him in his stall
This sounds kinda stupid but reading to your horse is really great. Also just sitting with him is great bonding.
I stretch my horse before i ride to help the girth and help stretch out their muscles before a hard work out. It makes a lot of a differences, try lateral leg stretches and body stretches it helps the whole body and legs