openingtree VS listudy

If you know his account on any chess sites you can take a look at it on https://www.openingtree.com/ and find a line he plays that is bad for him, intentionally go for it and have some prep once you there.

I would recommend https://www.openingtree.com/ to start.

Might it be openingtree?

openingtree(https://www.openingtree.com/) will analyze hundreds of your games and let you see, move by move, where you tend to go wrong.

The 3rd thing is that the account is 9 days old. There is some really suspicious behavior here, including his best win being against a 2178 and his worst loss being against a 1214! (according to https://www.openingtree.com/).

Maybe use this website: https://www.openingtree.com/ and filter the games from a certain time frame, like you played that opening exclusively for a week, and then see what happened there, what were the most common positions, and that's the direction I'd take to learn from. Worrying too much about main lines doesn't have much practical value

https://www.openingtree.com/ contains both lichess and chesscom games. Here's Eric Rosen explaining how this works https://www.youtube.com/watch?v=AJ66-HqdpXE

It comes with experience. There is a website called listudy.org that has a section called “Blind Tactics” that might help with visualization.

Listudy: Memorise openings with spaced repetition. Chess Endgame Training Chessercise: Practice chess with YouTube. Chess Madra: Build and practise an opening repertoire. Aimchess: Learn your strengths and weaknesses.

If you are trying to practice a certain opening, I would highly recommend listudy.org just to build that spaced repetition in your head.

I find https://listudy.org very useful for drilling lines. I don't see it mentioned often, but it allows you to import any lichess study (selfmade or other) into it and it'll pick a random line that's up to you to correctly play out until the end. Works very well if you do it enough

I use private Lichess Studies to store/build my repertoire. Start "choosing" your preferred responses to various opening moves and store them there. Start 1 move deep at a time and branch out slowly. At low level of play it's actually better to go just a few moves deep and have some canned responses to common bad moves from your opponents. You can import your lichess study into listudy.org which turns your saved opening prep into spaced repetition exercises to practice.

listudy.org

Second, you can check out https://listudy.org which can do this with lichess studies.