I have been playing in a bunch of different games here at the World Boardgaming Championships and it has given me a much clearer picture of how people play games and how good they are. People told me ahead of time that the heats to qualify for finals games are really easy, but I didn't realize quite how much so. There are of course people who show up for games who don't really know how to play, and that is certainly a source of easy wins, but there are a lot of people who just don't know how to win.
And that isn't to say they are terrible or dumb or anything, just that there are specific ways you go about training yourself to be excellent at games and most of those ways are to surround yourself with really great people who can push you to excel. There aren't that many people who have a tremendous intuitive grasp of strategy games and as such it is really unlikely that a given person will have a group of those people around them to make them better.
I credit the Lounge in university for much of my education in this way. I have the natural talent, but being in the company of people who see things quickly, who can find things I miss, made me better in ways that are impossible to achieve on your own. That training isn't something you can pick up in a day or a week either, and if you end up at WBC without having people in your circle who are amazing then you aren't going to be the shark - your skills won't be honed enough.
It takes a certain attitude too. You have to desperately want to be the best. In fact you have to want to play against the best people who are happy to smash you to smithereens so you can learn how they do it. The desire to learn needs to be much stronger than the desire to do well in a single game if you want to get better.
That isn't to say this is the right way to play - everyone should play and socialize however works for them. For some intense pressure to learn and win and improve isn't their thing. But if you want to win, that pressure from others who also have that desire is necessary.
That general game training lets you see things. It lets you pick up games and win immediately, just because you can see how you have to be in order to win. I have seen that so much - the people with the best group support just step into games and dominate, even if they don't know the rules well or miss important things.
Practice is good. Study is good. But the key to success here and elsewhere in games is to be surrounded by cutthroat competitors eager to improve, and to push them to be better so they can do the same for you.