I shoot a ton of barns and what seems to be missing here is you taking time to shoot a photograph instead of taking a "snapshot". I know that may upset people but I personally think there is indeed a difference.
These shoots look like you were driving past them, and just snapped away. If you had taken the time to get out and compose the shots I think they would have been quite a bit better. They all look rather flat also. Not sure if you did any post processing or not, but they look like they're pretty much right out of the camera.
Lastly, watch your horizons, and try not to "center up" so much.