The art of decision-making has gained in importance and will probably continue to do so in the coming decades. In the "free world," we have many options for making important life decisions that did not exist in this variety a few decades ago. These decisions affect our education, partnership, career choice, place of living, aspects of health and wellbeing, finances, and many other areas. It's not easy to make good decisions — and often it never becomes clear whether a decision was the "right" one.
So how to make good decisions and how to learn this skill? Some people argue that their best decisions in life were pure "gut decisions" based on their feelings, intuition, and experience. On the other hand, being able to think clearly can certainly help make good decisions. And also stress tolerance and coolness is needed. A good combination of these factors might be the way to go, with weight given to one or the other depending on the nature of the decision to be made.
Coming back to Petar’s initial question: What to study? To improve decision-making skills, I think an education that trains analytical thinking (science, mathematics, engineering) is beneficial, but should be combined with languages and possibly some creative arts.