I ride strange and maybe broke horses as a job... there is no arena or available round-pen yet, so for the ones that are maybe broke, I'll first establish that I'm boss. Before I get on, I'll treat them as a colt, and pull their nose over to face me, and get on. I'll let them relax, set myself deep and ask for a walk, then go in circles until I have a feel of the horse, and their training (or lack thereof) and continue to ride them until I believe I've got them working good at their training level. Some it might be just stopping and backing up good, or on others, it's doing good loping figure eights.
There was one pony who was soooo barn sour, we got chased out into the field with a lunge whip... teehehe. The next time I rode her, she didn't fuss too much about leaving.
One thing you have to find out first, is what works for the horse. Not all horses ride exactly the same, as a rider, you have to make adjustments to that, before you can bring the horse over to how you want a horse to ride.
Sometimes, if I find that a horse is unwilling to move out, I'll take them for a breeze down the field and then put them away, but I don't recommend that one.