One of the things about being effective in belief change is the way you interject and weaken undesired mental images and strengthen desired images in people’s minds.
For instance, someone may have a very firm belief (maybe even paranoia) that someone is plotting against them in the office (lol — well who isn’t). In this case, you can basically do a number of things to weaken those mental images.
One way is to use a simple pattern interrupt. If you are adept enough, you can weave this in smoothly without causing a serious break in rapport. Another way that is common is to offer counter examples within your conversation itself. The targeted undesired belief can then be diminished greatly.