hey M.,
we went through his with the not sharing and not listening. what i had to end up doing is getting tough. if he didn't share, then the toy got taken away. if we were out and he didn't listen, we gave a warning and then if the behavior continued we immediately left. EVERYTIME we go somewhere i prepare him in the car with rules and my expectations and what the consequence will be if he doesn't follow them. we do this over and over in the car. sharing can be dealt with with a toy time out. if mine is out of line with not sharing or hitting with a toy, i take it away for the day and put it in toy time out.
time out chair is also quite helpful. follow the supernanny technique. it really works. you just have to be consistent with it. hope this helps!