I have to parrot what others say about playing slower chess. I was around 900 when I started on chess.com and peaked around 1600. I did regress though as I lost the obsession.

This is what I did over many years:

- Playing alot of slow chess. This allows you to explore and learn from the exploration, but also gives you a small amount of pressure.

- Studying openings with mobile apps

- Consuming everything chess through books, apps, and videos. I loved watching analysis of the masters.

- Focusing on tactics over strategy. I learned from a really good chess player that strategy is more of an experts tool. I was never going to be an expert.

- Chess puzzles. This helps with pattern recognition, especially in blitz.

My rating is usually around 1200-1400, so not much higher than yours. I play on lichess.

One piece of advice I got from a very high rated player was to play longer time controls. He said, “playing only blitz you’ll just keep making the same mistakes over and over without even realising it”. I have found this to be true, and generally prefer the chess I play at Rapid time controls.