You change the minds of the fixed type more through experience and transformative impositions on them. They learn through doing (Taurus and Leo) rather than reading and thinking. They build themselves up on what they know (Aquarius and Scorpio) and become attached to their knowledge. There is less care for details and more for the bulk, whenever a detail is important to the context of whatever they are doing they will hone in on it, but generally can be unaware, cliquish and intellectually caged from thought structures and dogmatic people.
With the fixed signs in intelligence, when ideas attack what has been made "theirs", whether its they're dogshite religion or some theory they have they are proud of, you have to go for the killing blow- transform them in order to get them to listen to you. If you don't do it, everytime you speak you build up an amount of arguments against their idea in their head, which they then put aside to try and build their own idea back up again.
There has to be emphasis in fixed signs. The chart ruler, Sun, Moon and the other rulers of the Angular houses, they all are important in determining this. If there is a mutable emphasis the person will be more open to concede and change. If there is cardinal emphasis there will either be extra charge in debates with this person, more being achieved in the conversation, or extra territorialism if they don't see eye to eye with you.