Here’s how I went from rock bottom to winning a Championship Title in only 2 years:
My full focus was on finding the few things that make a big difference in Chess.
I started out by going through my games and creating a list of my biggest mistakes.
I realized that I lost (or failed to win) roughly 80% of my games due to Tactics & Calculation mistakes.
Oh wow, that is a lot! This number can be explained in two ways:
1) Tactics really do decide most games, even on Grandmaster Level.
2) Suffering from a Brain Injury, I had difficulties to focus and thus my blunders increased.
Finding an area that was accountable for so many mistakes gave me hope. If I manage to decrease the amount of tactical mistakes, my rating will increase dramatically!
So how can one improve the tactical & combination skills?
By solving exercises similar to the positions I will face during a game!
Instead of spending time on unnecessary things, I now tried to solve exercises whenever I was able to focus well.
This training alone was more impactful than hundreds of hours of opening study.
Alongside this training, my main aim was to keep my decisions as simple as possible.
My body simply wasn't ready for a tournament full of nightly preparations, remembering engine lines & complicated tactical battles.
The key was to:
1) Get positions with reasonably simple ideas and
2) To be able to play them better than my opponents.
That meant logical opening concepts instead of long and difficult to remember Engine lines.
It meant studying the structures before the tournament, so I did not have to review much before a given game.
Understanding endgame ideas instead of blindly remembering some sequences.
In short: not a lot of memorization but counting on understanding, so that even on a bad day my subconscious mind (or intuition) can take over.