“As with everything, fighting takes practice. Anything can look easy if you’re watching someone who’s mastered whatever it is they are doing, but what you don’t see is the hours and years of effort that go into perfecting their craft. I am sure you can plow a field in a fraction of the time it would take me for this very reason. Sword fighting is no different. Practice will allow you to react without thought to events, and even to anticipate those events. It becomes a form of foresight, the ability to look into the future and know exactly what your opponent will do even before he does. WIthout practice, you’ll need to think too much. When fighting a more skilled opponent, even a split second of hesitation can get you killed.”
– Michael J. Sullivan, Theft of Swords
Some people can make playing a guitar look easy. Some people makes it look easy to stand in front of hundreds of people and make them laugh, cry or understand something completely new. The reason it looks easy is that they have practiced for years to become that good. What practice does is to make the standard moves into the subconscious which allows them to focus on what is important. When I learned how to drive my focus was mostly on shifting gears, and remembering which pedal was the break and which was the clutch. After practicing driving my focus slowly moved away from those things and on to what was important; looking at the traffic, watching out for pedestrians and bicycles.
The same thing happens when practicing to give presentations. Instead of focusing on exactly what to say, how to stand and trying to keep your voice from trembling. You can start focusing on how the audience reacts, their questions and then follow that to make sure your point gets across instead of blindly following your script.
Experience also give you the ability to predict what will most likely happen and prepare for that, while someone without the experience have to constantly react to all the new situations.
Practice gives you time to focus on what is important.