The difference between understanding and believing is Science. Science will turn you from believing to understanding. The more things you understand instead of believe, the better equipped you are in making decisions related to your life. Aim to understand instead of believe.
The two foundational pillars of science, or to understand something, are observation and measurement. To understand something, you should be able to observe it. It need not be visual. It could be abstract, such as a mathematical result, or logic. The other pillar is measurement. Measurement need not necessarily be numerical with some units, such as 10 miles. It could instead be taxonomy.
So, when you come across something new or seek to improve something, try to understand it. First, define what is it that you are trying to understand. This is actually hard in many cases! Next, observe it, while also coming up with techniques to measure its characteristics.
Given a set of inputs, you can produce a result based on what you believe in, or what you understand. The correctness and quality of the result will be better when it is produced based on what you understand.