What separates a 6XX+ ELO player from a 4XX ELO player?

[Pistol Star]

For me thing that the most improved my game is playing strong opponents. Having many games with opponents way below your level is very boring and I think develops many bad habits. When you wait for an opponent I highly advise to filter in an options to only be matched to ones on your level. Even better if you can make friends with top players and discuss mistakes with them.

Agreed. But a few games versus weak(er) opponents can also help to better understand just HOW powerful certain principles are and what happens when you use them vs such opponents in terms of margin of victories.

Like you can in more detail understand what strategies (mainly their strategies) just don't work at all and why.
You can further understand how the math of the game works, because they gift you so many extremely high scoring turns, while they are going for low scoring turns and they also gift you opportunities to block them extremely hard.
When you do get an optimal opportunity to block them, then they are forced into low(er) scoring turns.
Especially when they don't understand the often strong value of the Take 2 Workers Actions, which is 99.9% of times the case, then these blocked turns will often become even (way) lower, because they tend to heavily overpay for certain actions, when the (by far) actual highest value action is the Take 2 Workers action. There are also quite frequently spots, in which it is correct to take the Take 2 Workers action twice in a round.

By already observing their ELO (similar ELO ranges tend to play similarly) and their in-game moves, we can quickly understand how their thought processes work and pretty much enforce huge mistakes to turn lost positions into winning positions or increase the margin of victory.
You can further learn what to absolutely never do by seeing how low their strategies score on average.

However, there will be the super rare losses against such opponents (usually on specific boards), where you can learn something about the board and see how a normally horrible strategy works at least not AS horribly on this specific board.
Then use this newly gained knowledge to further optimize your strategic and tactical approaches for this board.
When you do lose against players with an ELO of below 300, you shouldn't blame luck.
You should actually pretty much never blame luck, because most games on below master level are with optimal play well winnable, even with (very) bad luck.
If you play perfectly, I think you should win like 99.8% of the games vs <300 ELO players, because they just blunder way too much.
Depending on the level of your weak opponent you can win games even up to over 100 points margins.

It's also important to realize that a let's say 650 ELO player isn't a 650 ELO player on each board.
They will have boards on which they are performing on let's say 730 ELO, because they understand this board better than the average board.
But then they will also have boards where they perform on 570 ELO. Overall this will even out and that's why they reach an average ELO of 650.
So there are instances where a on average lower rated player is actually the (clear) favorite in a game against a on average higher rated player.

There are also boards with a higher luck factor compared to others.
I personally think that board 5 is the board with the by far highest skill factor, followed by board 9.
I think board 1 is the board with the highest luck factor.

[DoctorFianchetto]

They will have boards on which they are performing on let's say 730 ELO, because they understand this board better than the average board.
But then they will also have boards where they perform on 570 ELO. Overall this will even out and that's why they reach an average ELO of 650.
So there are instances where a on average lower rated player is actually the (clear) favorite in a game against a on average higher rated player.

As a novice player this surprises me that the strategies can differ across different boards, and that players can be better on one board than another. But like most things in Castle of Burgundy I can make an analogy to chess where different players are stronger in different types of positions reached from different openings.

On the topic of reviewing one's games, is the community open to reviewing games that are shared on here with the player's thoughts and analysis? That's something I am considering doing. I play infrequently, maybe one game a month, so it wouldn't be some kind of huge spam.

[mrTakeMSO]

CoB can be played in two and four players, there is a big difference imho because in 4 you can see all the tiles. You played more which one ?