Some great advice here already – I agree with all of the above. The answer is in increasing the horse’s sensitivity, not in producing greater avoidance strategies. There are always those who recommend stronger bits – (why are there so many?!) – as a short cut or a temporary fix. But you pay in the long run.
As a rule, I always transition my horses to ride bitless – but it takes some time to get a bitted horse to collect properly without one if he has been taught to balance on the bit. Getting the horse to balance takes some transitioning. I’d recommend just riding bareback, horse in a halter in a very small arena. Bareback sometimes slows the horse down and makes the rider pay attention better to seat cues, to sit more balanced, and while focused on the seat, the rider is less likely to go to the hands for control. It’s more informal and less pressure. Remember to relax yourself, too! Be fluid.
Sometimes the horse will relax better without a bit, and a calmer horse is a safer horse. A calm horse learns better, too. (If you trail ride, a bitless horse is less likely to spook and if spooking doesn’t spook badly.)
If you aren’t comfortable riding bareback, go ahead and try the halter headstall approach in a saddle, but stay in a round ring or smaller arena. If the horse ‘lays on your hands’ you will have to adjust your seat to help him balance, and give him time to learn to round himself under seat cues by driving him forward with your legs and sitting deeper and straighter.
Work in short sessions helps both of you gain confidence and build balance. Going bitless sometimes takes a while, but then the responsiveness of the horse becomes more than a little bit amazing. When you do need to use the bit in competition, you have a much more subtle, balanced and sensitive partner, and best of all, his mouth does not hurt.
It seems counterintuitive, much of horse work is, because the horse does not think like we do. Less is more – words to live by with horses. Good luck.
Alois Podhajsky: “When I hear somebody talk about a horse being stupid, I figure it’s a sure sign that animal has outfoxed them. ...