Whenever you find yourself about to express a belief, ask yourself if you really believe it it first. This works for me, but may not work for people not feeling curiosity or for people not already in the habit of being honest with themselves.

...often that thought causes me to not know what I believe.

Of course the hard part is figuring out a way to reliably put people in a situation where they will find themselves rationalizing. Social pressure would work on a lot of people, but probably not so well on LW types.