For steaks I like to use very high heat to sear the steaks to seal in the juices. Pan frying works well with olive oil to the point of almost smoking. Cook to the point of searing, possibly showing caramelization, turn and sear the second side. If further cooking is desired turn the heat way down and partially cover so as not to steam, but hold heat on the first side as well as the bottom side. Remove before reaching the desired doneness as it will continue to cook some after removal from heat. Be careful to not over cook. Letting the steak “rest” for a short period allows the juices to redistribute throughout the steak. For best results bison should be cooked rare to medium. Well-done can cause dryness and toughness.
I feel that the best tasting bison is served medium rare to medium. As grass fed bison is so lean it is easy to over cook, and like other lean meats, deer or elk for example, it gets pretty tough or dry if it is over cooked. And no one is going to enjoy a dry tough steak. So, my personal advice is to not over cook it, error on the side of too rare than too done. You can always throw it back on the heat if you need to, you can’t un-cook it.