In my view, one of the easiest steps toward becoming more rational - counterintuitive as it may seem - is to start being less certain of yourself. What people often do is form an opinion based on limited information, and that opinion quickly becomes part of their identity. They then irrationally defend it tooth and nail, seeking out supporting evidence and dismissing anything that challenges it.
When you do the opposite - admit that you don’t know or aren’t sure - you keep your mind open to new information, allowing your thinking to evolve over time. It’s perfectly fine to have opinions, but there’s a big difference between saying “this is how it is” and saying “this is my current view on it.” Absolute truths are rare, even in science. Most of what we consider facts are just our current best understanding of a subject.