How does one get better at boardgames generally?
Just before Christmas I went to see a gaming friend and taught him Splendor Duel, a game I'd played a number of times already. He then went on to beat me five straight times in a row which was a fun but chastening experience.
After the first couple of times, I tried looking at the game from different angles to see if I could see what I was doing wrong or, perhaps more accurately, to see what I could be doing better. Whatever I spotted, I was clearly wrong as it didn't help at all!
As a general rule, this kind of thing puts me off more abstract games like Splendor Duel because I find it very hard in abstracts to see where a problem is and improve it. To give a crude example if you're playing Twilight Struggle for the first time, and you put influence in Egypt before you learn there's a card that fills Egypt with USSR influence, you'll know the next time you play that, as a general rule, it's a bad idea to manually put influence in Egypt. You can see exactly the mistake you made and exactly what's needed to correct it.
But with abstract/efficiency games that kind of exercise is impossible. There's no one point at which you made an error you can learn from. In fact, the only real feedback you get is that you lost, so it's very hard to pinpoint what you did wrong and what you need to do better.
So: what can I do in Splendor Duel and similar games to *play better* generally from the off and how can I better translate my experience into success?