How to analyse games?

Opening phase

Start off with asking yourself a question: ''Did I get a good position after the opening?. Reflect on any mistakes or inaccuracies you made and consider how you might improve next time. If you didn’t make any clear errors, explore alternative moves or strategies for the opening you chose to expand your repertoire.
If you faced difficulties, dig into the principles you may have violated and understand why mistakes happened. Ask yourself, be critical and reflect on the underlying flaws in your thought process.

I have reached this position with Black pieces. Although, I played b4 and my choice was good enough, I have checked other alternatives 9... Nbd7, Bg4, Na6, a5 , Nfd7 after the game and explored them too to have a better understanding of various structures in that system. You can see some lines I was investigating. Next time I have a wide number of options to choose from. I can say that I became more knowledgeable in this system.

Middlegame stage

In the middlegame everything comes down to our ability to calculate and evaluate variations. It is the hardest part of the game to understand. We have to pay attention to the cause of our mistakes and make the right conclusions. Let me show a few examples of how one can do it.
Example 1

This example is from the same game I showed before, I totally misplayed it and didn't find the right plan, so what? Reflection part is the most important - what should I do or how should I think to avoid similar confusion in the subsequent games. My reflection and analysis with engine proved me that I underestimated the importance of development and overestimated the material factor. I rejected all lines where I had to sacrifice material, so next time I will be aware of that. I made some conclusions that could improve my chances to handle complicated positions next time.

Example 2

This middlegame example can teach one a lot. White lost the game in a slighlty worse position. Why did it happen? The White player didn't consider his opponent ideas. He should change his mindset and pay attention to this aspect of the game. This player could solve puzzles on the topic of prophylaxis or practice more. While playing, he must stay alert and improve his thought process. It is important to contact a coach for those who are just starting out. Players below 2100 quite often struggle to make correct conclusions. They look through games superficially and their thought process remains the same.

Conclusions

Reflection is the key! It is of outmost importance to understand the causes of your mistakes. It could be that you calculate poorly, or you are able to calculate well, but lazy to do so. Your problem may lie in superficial understanding of plans arising from your opening. Explore your thinking system and adjust it, keep making it better and better. Learn at least one lesson from any game you have played. Good luck in your self-reflection chess journey! If you need help , contact me here at lichess or join my Telegram channel https://t.me/learnchess03 , where I post a lot of chess content on various topics. I am building a community of chess enthusiasts who are eager to improve and reflect on chess with me!