By finding shortcuts that work most of the time. You enter a sports store and start looking at the different models. Some have what look to be shock absorbers, some have chains and sprockets, some have cables and pulleys, others have levers that balance on a fulcrum. At this point, you have a choice. With several months of concerted effort and concentration, you may be able come to your own conclusions about which mechanical system is best.
Heuristics work pretty well most of the time.
But sometimes you have to think in order to survive. Sometimes, you just have to think in order to get yourself out of a jam or improve your state in life. We tend to idle, even when we should be thinking. Only when a topic is important to us and actually requires effortful thought do we engage our brains and make them do some real work. The rest of the time, we're coasting, baby.