Only miles and confident riding will sort out his spookiness undersaddle. When he gets spooky or "looky" and stuff, don't just sit there and try to ride it out hoping he won't spook, or that he will just settle down. Give him a job to do, and refocus his mind. So if he is tense and looking at something around him, start doing circles or serpentines, or just go back and forth near that object...you're not focusing on making him approach it, you are only focusing on getting his attention back on you, and to help him use his mind, rather than just reacting to everything around him.
Example: one afternoon when I was riding my mare, there was another horse and rider in the arena, and she was a very uh...loud rider, constantly yelling at her horse, clicking, kissing, whistling, etc...well my mare wasn't quite sure what to take of that, and got nervous. Instead of trying to hold her at a walk, I just put her feet (and thus mind) to work...since there was only two of us in the arena at that time, I was able to use the entire center of the arena while the other rider rode the rail. We did circle work, and serpentines, etc, at trot and canter. When I felt my mare start to relax and settle down, I eventually stopped her near enough to the rail so she could still hear the other rider, and just let her stand and relax there; if she would have gotten nervous again, I would have put her back to work, but she stood, leg cocked, and fell asleep. I then walked her around the arena to cool her out, still focusing on keeping her full attention, but keeping it slow. When she was cooled out a bit, I set her by the rail again, and let her rest some more.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."