In most of the pics you posted, the sky and any whites or reflections are truly blown out. Take the last photo for instance, where does his helmet stop and the sky begin?
Maybe Add some fill flash, meter the scene and subjects, shoot in raw mode, try lower ISO, etc etc
If you leave your camera set on AUTO everything most of the time, try setting the camera to "M" and adjusting the settings manually. See how you like the results and practice practice practice etc.
ALSO in the fourth pic from the top, if you had some flash available you could drag your shutter, still get stop motion from the flash but some motion blur from the guy as he does his stunt. Just a few thoughts, hope they help