advice

advice on the following game,

I have been stuck on 1400 for over a year.  

[Event "Live Chess"]
[Site "Chess.com"]
[Date "2021.03.09"]
[Round "-"]
[White "MEzia"]
[Black "noahmarkewitz11"]
[Result "1-0"]
[CurrentPosition "4r2k/2p5/p1q1P1Q1/1p1pBP2/1P4p1/P1P5/8/5R1K b - -"]
[Timezone "UTC"]
[ECO "C26"]
[ECOUrl "https://www.chess.com/openings/Vienna-Game-Falkbeer-Stanley-Variation-3...Bc5"]
[UTCDate "2021.03.09"]
[UTCTime "23:48:45"]
[WhiteElo "1329"]
[BlackElo "1377"]
[TimeControl "1800"]
[Termination "MEzia won by checkmate"]
[StartTime "23:48:45"]
[EndDate "2021.03.10"]
[EndTime "00:42:55"]
[Link "https://www.chess.com/game/live/9072485639"]

1. e4 e5 2. Bc4 Nf6 3. Nc3 Bc5 4. h3 O-O 5. Nf3 d6 6. d3 a6 7. a3 Nc6 8. Bg5 h6
9. Bh4 g5 10. Bg3 Be6 11. b4 Ba7 12. O-O b5 13. Ba2 Nd4 14. Nxd4 Bxd4 15. Qd2
Nh5 16. Kh1 Bxa2 17. Rxa2 f5 18. Ne2 f4 19. Bh2 Bb6 20. f3 Be3 21. Qc3 Rc8 22.
d4 exd4 {INACCURACY (+0.39)} ({(-0.76) The best move was} 22... d5 23. dxe5 dxe4
24. fxe4 c5 25. bxc5 Rxc5 26. Qb3+ Kg7 27. a4 Qd2 28. c3 Qd3 29. axb5 Rxb5 30.
Qd1 Qxd1 31. Rxd1 Rxe5 32. Nd4 Bxd4 33. Rxd4) 23. Nxd4 {Critical move.} 23...
Qf6 {INACCURACY (+1.04)} ({(0.00) The best move was} 23... Bxd4 24. Qxd4 Qf6 25.
Qd2 Ng3+ 26. Bxg3 fxg3 27. c4 g4 28. cxb5 axb5 29. Qe1 Qe5 30. hxg4 c5 31. a4
cxb4 32. Qxb4 bxa4 33. Rxa4 Qg5) 24. Qb3+ Kh8 25. Nf5 Ng7? ± {MISTAKE (+3.63)}
({(+0.48) The best move was} 25... Bd4 26. c4 Be5 27. Rc2 Qe6 28. Qd3 c5 29.
Rfc1 cxb4 30. axb4 Rxc4 31. Rxc4 bxc4 32. Rxc4 d5 33. Rc1 dxe4 34. fxe4 Re8 35.
Nd4 Bxd4 36. Qxd4+ Qe5 37. Qxe5+ Rxe5) 26. Nxe3 fxe3 27. Qxe3 Rce8 28. c3
{INACCURACY (+2.17)} ({(+3.07) The best move was} 28. Qd3 Qe6 29. Raa1 h5 30.
Rae1 Kh7 31. f4 gxf4 32. Rxf4 Kg8 33. Rxf8+ Rxf8 34. Qg3 Re8 35. Qh4) 28... d5
29. Raf2 Nf5? {MISTAKE (+5.25)} ({(+1.89) The best move was} 29... Qg6 30. Bxc7
dxe4 31. fxe4 Rxf2 32. Qxf2 Rxe4 33. Kh2 Kh7 34. Re1 Rxe1 35. Qxe1 Qc6 36. Qb1+
Kg8 37. Qa2+ Kh7 38. Qc2+ Kg8 39. Bg3 Nh5 40. Qb3+ Kg7 41. Bf2 Qd6+ 42. Kg1) 30.
Qe2?? = {BLUNDER (+0.88)} ({(+5.25) The best move was} 30. Qd2 dxe4 31. fxe4
Rxe4 32. Rxf5 Qxf5 33. Rxf5 Rxf5 34. Bg1 Rf8 35. Qd3 Re1 36. Qg6 Rff1 37. Kh2
Rxg1 38. Qxh6+ Kg8 39. Qxg5+ Kf7 40. Qf4+ Kg6) 30... Nh4? ± {MISTAKE (+4.25)
Critical mistake.} ({(+0.88) The best move was} 30... Qxc3 31. Rd1 Ne3 32. Re1
Nc4 33. Bxc7 d4 34. Rd1 Ne3 35. Bd6 Nxd1 36. Qxd1 Rxe4 37. Rd2 Rd8 38. fxe4 Rxd6
39. e5 Re6 40. Rxd4 Rxe5 41. Kh2 Re1) 31. e5 Qf5 32. f4 g4? {MISTAKE (+7.51)}
({(+4.87) The best move was} 32... Qe4 33. Qd2 Re6 34. Re1 Qg6 35. Qxd5 g4 36.
hxg4 Qxg4 37. f5 Nxf5 38. Qxe6 Ng3+ 39. Bxg3 Qxe6 40. Rxf8+ Kg7 41. Rf6 Qd5 42.
Kh2 Qc4) 33. hxg4 Qg6 {INACCURACY (+8.96)} ({(+6.78) The best move was} 33...
Qe4 34. f5 h5 35. Qd2 Qxg4 36. f6 Re6 37. Qxd5 Rf7 38. Bg3 c6 39. Qd3 Ng6 40.
Qf5 Kg8 41. Rd2 Re8 42. Qxg4 hxg4 43. Rf5 Kf8) 34. g3 Nf5 35. gxf5 Qxf5 36. g4
Qg6 37. Rg2 Qc6 38. Qe3 Rg8 39. f5 h5 {INACCURACY (+17.67)} ({(+9.48) The best
move was} 39... d4 40. Qh3 dxc3 41. e6 Kh7 42. Bf4 Rxe6 43. fxe6 Rg6 44. Rc1
Qxe6 45. Rxc3 c6 46. g5 Qxh3+ 47. Rxh3 h5 48. Rxh5+ Kg8 49. Rh6 Kf7 50. Rxg6
Kxg6) 40. e6 Rxg4?? {BLUNDER (♔ Mate in 4)} ({(+19.44) The best move was} 40...
Kh7 41. g5 Rg7 42. g6+ Kg8 43. f6 Qc4 44. f7+ Kf8 45. fxe8=Q+ Kxe8 46. Rf7 Qxb4
47. axb4 c6 48. Rxg7 a5 49. bxa5 h4) 41. Qh6+ Kg8 □ 42. Rxg4+ hxg4 □ 43. Qg6+
Kh8 44. Be5# 1-0

I was impressed by your first 19 moves, and even up to move ~30 or so there are no big problems.

A few things that come to mind.

First thing:

12...b5 and 17...f5
At least in the first half of the game, it's usually better to choose one area to push your pawns like this. When you push on both sides it weakens a lot of squares, so if your opponent infiltrates into your position later it will tend to be better for them than it would have been. I liked your idea of f5. A lot of Italian structures will feature a plan like c6+d5 by black, or maybe b5+a5 (when it's a pawn break). But having already committed to g5 it seems to me that the kingside and the f5 move are a natural way to play.

However 20.f3 really locked up that side of the board. Black's position really wanted you to play 19...f3. This is a common sort of move that players will even go for when they have to sacrifice a pawn to do it. It damages the structure around your opponent's king and opens the f file for you. When you invest in an area by moving up a lot of pawns, it's important that you can eventually open some files or diagonals in that area so your pieces can infiltrate into your opponent's position. When the kingside became locked that was bad for you.

---

Second thing:

People always talk about the opening principles like prioritize piece development, minimize pawn moves, keep your king safe, etc, but these are actually good principles for the entire game. With that in mind here's a position from the game.

Black to move

-

-

Your move was Be3
I probably wouldn't calculate much here. I'd simply see my knight is bad, so I want to activate it a lot like developing in the opening. I'd want to play Ng7-e6 to add influence to d4, or Nf6 to add influence to d5. Since the kingside became locked, all the important pawn breaks are on the the d and c files, and the knight wants to be part of the action.

Your move 20 seemed to be a gut reaction. 20...Be3 is what I like to jokingly call "hoping I get to move twice in a row." Instead of that, think to yourself, "what really good thing does my bishop do on e3?" and if the only answer is "I hope he doesn't see I'm attacking his queen" then don't play that move. This may seem like a small bit of advice, but it can really change the way you play (or at least really cause you to question your moves and consider alternatives).

---

Third thing

Always tactics. Maybe you were low on time at this point, but 29...Nf5 did what you wanted, it chased the queen away... so now you can take the c3 pawn, but you don't.

Calculating forcing moves is tedious... it's not fun but winning games is fun, and if you want to improve it's always worth it to work on improving your calculation habits. There should be zero "automatic" moves in your games. Always look at a wide range of captures and checks at the beginning of every move. Even if you end up spending 99% of your time looking at 1 move, that's fine, but at the very least you need to stop before each move and cast a wide net at the beginning of your turn. When the engine shows you a tactic you missed, you want to be able to say "I considered the first move but I didn't realize how good it was" and if the first move was a capture or check you never want to have to say " I didn't even consider that."

I know you're not a beginner, but everyone should read something like this (link below) at least once, especially anyone below ~1600:

https://www.chess.com/forum/view/for-beginners/the-most-important-concept-for-all-beginners