Yeah, maybe put some shelves, the ones you have to reach with a forklift or something. Maybe some big barrels in the corner, some grease on the floor or some skid marks or something.
The thing about the roof, and I have no idea how to change that, is that it kind of lacks texture compared to other surfaces (the bricks, the door, the floor). You could try to add some beams, this size of a room, and without columns, has to have support beams on the ceiling, that'll also give it more detail without the need for a more pronounced texture.
Also the hooks in the foreground don't look "hookey" if you know what I mean, maybe bend them a bit more.