Learn to question, but don’t fall into the trap of skepticism. There are many skeptical people in the world that doubt everything. But they simply are in the habit of being negative and are not exercising their intellect. If you aspire to master the ability to reason, you must learn to evaluate the information you receive.
What was the source of the information? Was the source biased in any way? Is the information subjective or objective? Is there an opposing viewpoint? Never believe something just because you heard it, read it in a book, or heard a celebrity say it. Always verify. Always authenticate.
Everyone has a bias. Just because someone is sincere doesn’t mean he is right. Learn to make up your own mind, leaving ample room for adjustment.