Sometimes in order to make a change happen, all you need to do is change the environment.
If you have analysts, developers, testers and users who don’t communicate very well you can help encourage better communication by changing the environment. Create a co-located space and then have them all work in that space together. The environmental change forces them to acknowledge each other’s presence and begin working together. Instead of “Hey, there’s a dangerous Morning Sun Star in here and I have to run away before it eats me”, you should get reactions like “Hey – there’s a user in here, I guess I’ll show them the changes I’m making to this screen to get some feedback”.