The same... :facepalm :facepalm
How can I improve as an 800 rated player with 2-3 years of experience

Analyze your games but also play sound openings. Lichess does it for free where you can see your mistakes and fix them like a puzzle. Also, play longer time controls. When I started, I was playing a lot of 10-minute games which is not bad but I should have been playing more 15-minute-plus games. You can just play one game and still do fine as long as it's one long game.
Do a lot of tactics and endgame puzzles so you can capitalize on your opponent's mistakes. Lichess has a puzzle feature where you can do puzzles that arise from certain openings but you can also do the standard ones if you want

I am also around your level and I find that the best way to improve quickly is to analyze your games, find out your common mistakes, and try to be aware of them when you play.

Thoroughly learn basic endings, pawn structures, and tactics. Don't play a lot of speed chess, play slow games instead and study them. Post your slow serious games on here with your thoughts and you'll get a lot better fast.

Improving Your Chess - Resources for Beginners and Beyond...
https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond
@1
"How can I improve as an 800 rated player"
++ A rating of 800 is a sign of frequent blunders. Always check your intended move is no blunder before you play it. Imagine your move played, verify it is no blunder, only then play it. Hang no pieces, hang no pawns. When your opponent hangs a piece or a pawn, then take it.

Hi!
If you don't play so often -and perhaps do not invest in improving activities either - it is not possible to get better. As an example, for an intermediate level player (rated 1100 - 1700), accordng to a survey based on Blitz ratngs at Chess.com, if you devoted 20 hours/week to chess activities (50% play, 50% improving activities like studying + solving excercises) working by your own (no coaching) then after a year you could reach 1300 - 1400 (expected). Of course there are people that improves faster, especially if they get help from a teacher or coach.
Good luck!

Hi!
If you don't play so often -and perhaps do not invest in improving activities either - it is not possible to get better. As an example, for an intermediate level player like you (rated 1200), accordng to a survey based on Blitz ratngs at Chess.com, if you devoted 20 hours/week to chess activities (50% play, 50% improving activities like studying + solving excercises) working by your own (no coaching) then after a year you could reach 1300 - 1400 (expected). Of course there are people that improves faster, especially if they get help from a teacher or coach.
Good luck!
I don't play often because I don't have a lot of time. How can I improve ?