There are many ways to improve as a player. All involve work and study.
One way to get good information is reviewing hand records after a session.
Some clubs and most tournaments offer hand records, which can be valuable tools for improving. It can be very helpful to get together with friends to review each deal. For best results, leave out the personal commentary and blame assessment.
When the session is over, get the hand records and find your two worst results. Look at them constructively and discuss them with the goal of seeing what might have been done. Do not use this time to blame your partner. Use the time to see what you might have done differently.
Here are two deals to show you how these discussions might go.
West leads the ♥A and ♥K and gives East a heart ruff. East leads a club back and West takes two club tricks. Down two and you have not taken a trick yet. East turns out to have the top two spades, so you are down four. Minus 1100 and most certainly a bad score. Adding insult to injury, you spot the ♦K in the East hand. They don’t have a thing their way.
How does your conversation go? Does North tell South not to open such trash? Does South tell North to stop raising to game every time he has five trumps?
This kind of talk leads nowhere. Better is if South observes that he had seven wasted points in diamonds and three low hearts. South could prove himself to be a sensational partner if he told North that 4♠ might have been cold if South had slightly different shape. Further, if East didn’t have both spade honors, he might have bid something and gone down. And so on. Here’s another.
You and partner are sitting East–West. West leads the ♦J, South winning the king in dummy. You note the dummy and the fact that it has four hearts. Would you bid 3NT or look for a major? Before you get your thoughts together, South plays the ♥A and ♥K and leads a heart to West’s queen. As East, what are your discards on these two hearts?
It looks like you can afford a diamond and you may wish to tell partner about your spades. At the table, East discarded the ♠10. You can see that a spade lead from West is a bad idea. West does lead a spade, and that gives South an easy trick that he might not otherwise get.
So how does your discussion go after the session is over? When you get to this board, you might talk briefly about North’s bid in an effort to hide the fact that you got a stinky result, but your side needs to discuss why it occurred. A bad East would say, “How good did you think my spades were? I was marked with a weak hand.”
That is a comment typical of a player who wants only to win the postmortem. A more sensible East would say, “My ten of spades was a bad choice. It was confusing. I should have played the queen of spades. That would tell you that I had all the spades from the queen down. I do not know what you would do with this information, but at least you would know what to expect.”
The short form of this article is that you should look at your bad results and try to find out what you and your partner could have done differently. Not what your partner should have done differently.