I agree with Pavan that it's usually just one small thing that I need to adjust. The problem I have is that it's not obvious to me what that small thing is, so often I self-diagnose the wrong thing, and then I have two things that need adjusting. So it's really helpful to me to have someone who really knows what he is doing look at me shoot once in a while and tell me what I need to correct. Often, even when it's pointed out to me, I can't feel what I'm doing wrong, but after I focus on the area that needs to be corrected for a while, I begin to be aware of when I'm doing it right and when I'm doing wrong.
An example would be moving my head on release. I'm not aware that I'm picking up my head, but when it's pointed out to me numerous times, I finally begin to feel it when I do it.
I don't feel too bad about having to do this. I used to be heavily into golf, and I read that Jack Nicklaus used to have a coach he would visit for a week every year to tweak his swing. I'm sure the coach couldn't play golf anywhere near as well as Jack could, but he could see things about Jack's swing that Jack couldn't see himself.