The Most Instructive Games of Chess Ever Played by Irving Chernev (1965)
https://chessbookreviews.wordpress.com/tag/most-instructive-games-of-chess-ever-played/
I have been studying chess for a solid 6 months now, but I can't progress past 1400
I found the Chernev book rather pat (and would not likely recommend it).
Are you sure that you saw the book as it would be for someone well below NM-level?
"... Excelling at Chess Calculation ... meant for those who have reached club strength and are now willing to invest some serious effort in rising to the next level -- towards mastery and perhaps beyond. ... , if you still lose a lot of games by blundering in level positions, forget this book ..."
https://web.archive.org/web/20140708233835/http://www.chesscafe.com/text/review457.pdf
https://web.archive.org/web/20140708103037/http://www.chesscafe.com/text/review324.pdf
https://web.archive.org/web/20140708084438/http://www.chesscafe.com/text/review402.pdf
https://web.archive.org/web/20140708092514/http://www.chesscafe.com/text/review463.pdf
Here are some reading possibilities that I often mention:
https://www.chess.com/article/view/how-to-play-positional-chess
https://www.chess.com/article/view/test-your-positional-chess
https://www.chess.com/article/view/do-you-really-understand-positional-chess
https://www.chess.com/article/view/get-ready-to-test-your-positional-chess-again
https://www.chess.com/article/view/can-you-pass-this-positional-chess-test
https://www.chess.com/article/view/how-to-calculate-long-term-advantages-in-chess
https://www.chess.com/article/view/learning-basic-pawn-structures
https://www.chess.com/article/view/learning-pawn-structure-for-chess-players-under-2000
https://www.chess.com/article/view/your-pawn-structure-is-your-friend
https://www.chess.com/article/view/more-pawn-structures
Simple Attacking Plans by Fred Wilson (2012)
https://web.archive.org/web/20140708090402/http://www.chesscafe.com/text/review874.pdf
http://dev.jeremysilman.com/shop/pc/Simple-Attacking-Plans-77p3731.htm
Logical Chess: Move by Move by Irving Chernev (1957)
https://web.archive.org/web/20140708104437/http://www.chesscafe.com/text/logichess.pdf
The Most Instructive Games of Chess Ever Played by Irving Chernev (1965)
https://chessbookreviews.wordpress.com/tag/most-instructive-games-of-chess-ever-played/
Winning Chess by Irving Chernev and Fred Reinfeld (1948)
https://web.archive.org/web/20140708093415/http://www.chesscafe.com/text/review919.pdf
Back to Basics: Tactics by Dan Heisman (2007)
https://web.archive.org/web/20140708233537/http://www.chesscafe.com/text/review585.pdf
https://www.chess.com/article/view/book-review-back-to-basics-tactics
https://static1.squarespace.com/static/5856bd64ff7c50433c3803db/t/5895fc0ca5790af7895297e4/1486224396755/btbtactics2excerpt.pdf
Seirawan stuff:
http://seagaard.dk/review/eng/bo_beginner/ev_winning_chess.asp?KATID=BO&ID=BO-Beginner
https://web.archive.org/web/20140708090229/http://www.chesscafe.com/text/review492.pdf
http://www.nystar.com/tamarkin/review1.htm
https://www.chess.com/article/view/book-review-winning-chess-endings
https://web.archive.org/web/20140708092617/http://www.chesscafe.com/text/review560.pdf
50 Essential Chess Lessons by Steve Giddins
https://web.archive.org/web/20140708100833/http://www.chesscafe.com/text/review534.pdf
http://www.gambitbooks.com/pdfs/50_Essential_Chess_Lessons.pdf
Amateur's Mind by Jeremy Silman
https://web.archive.org/web/20140708094419/http://www.chesscafe.com/text/ammind.pdf
https://www.silmanjamespress.com/shop/chess/amateurs-mind-the-2nd-edition/
Simple Chess by Stean
https://web.archive.org/web/20140708104258/http://www.chesscafe.com/text/review400.pdf
http://store.doverpublications.com/0486424200.html
Chess Endgames for Kids by Karsten Müller (2015)
https://chessbookreviews.wordpress.com/tag/chess-endgames-for-kids/
http://www.gambitbooks.com/pdfs/Chess_Endgames_for_Kids.pdf
Silman’s Complete Endgame Course
https://web.archive.org/web/20140708103149/http://www.chesscafe.com/text/review594.pdf
https://www.silmanjamespress.com/shop/chess/silmans-complete-endgame-course/
http://theweekinchess.com/john-watson-reviews/theres-an-end-to-it-all
"... If it’s instruction, you look for an author that addresses players at your level (buying something that’s too advanced won’t help you at all). This means that a classic book that is revered by many people might not be useful for you. ..." - IM Jeremy Silman (2015)
https://www.chess.com/article/view/the-best-chess-books-ever
Look, face it. You simply may not have the raw talent to ever become a really strong player. Nevertheless, just keep on playing, follow all the excellent advice that others have given you and enjoy the game. I have seen folks like yourself that actually have gotten better by not pressuring themselves to attain an unrealistic goal. Think of all the tennis players and golfers who are not particularly good, have very little inborn talent yet work as hard as they can to improve. Despite years of hitting a "ceiling" of skill improvement, they still play for the sheer sake of enjoying the activity.
You're playing London System, but you can't really handle it. For instance here your opponent wants to exchange your strong blacksquared bishop and you let him do it. Also your light-squared bishop doesn't feel good on d3 square in King's side fianchetto systems e. g. King's Indian Defense, Grunfeld and etc:
So the point of playing h3 is to create a safe square for your bishop on h2 and if your opponent goes for it then you play Bh2.
Overall your main problem is that you don't have essential strategical and endgame knowledge. If you are interested in coaching - then I can be your coach. But if you want to study by your own I can suggest reading "My system" by Aron Nimzowitsch.
This is correct. My first thought when I looked at your games was you know some opening moves but I don't think you know always why they are being played.
My System is your friend. That or an endgame book - seriously. Amazing how a good knowledge of the endgame will change your move selections during the game.
Also, play some longer games where you have time to think. Analysing blitz is generally speaking not a good use of time in my view.
Good luck and stick with it. I played for 35 years before getting my FIDE rating over 2000.
Find an old copy of Winning Chess ( How to see three moves ahead) or Logical Chess Move by Move they helped me many years ago.

Do you already settle on some openings? Find out who the best players are in them. Find their games, go through them.
I feel like this is such an important tip.
When I was new I looked only at main lines or what the engine wanted me to play in the opening... but you'll have much better success by looking at what various GMs are doing, and then after you see a few different systems / ideas, you can pick something that appeals to you.
And yeah, this takes a lot of time, because (ideally) you see a lot of different approaches. Don't just look at modern games or top tournaments.

You're playing London System, but you can't really handle it. For instance here your opponent wants to exchange your strong blacksquared bishop and you let him do it. Also your light-squared bishop doesn't feel good on d3 square in King's side fianchetto systems e. g. King's Indian Defense, Grunfeld and etc:
So the point of playing h3 is to create a safe square for your bishop on h2 and if your opponent goes for it then you play Bh2.
Overall your main problem is that you don't have essential strategical and endgame knowledge. If you are interested in coaching - then I can be your coach. But if you want to study by your own I can suggest reading "My system" by Aron Nimzowitsch.
Thanks for the advice! Indeed, I pushed h3 to create an escape square for my bishop but eventually thought it would be awkward to retreat my bishop to h2 especially if my opponent would castle king's side. So I figured I'd rather have a semi open file for my rook after castling. What could have been a good developing strategy after Bh2?
Also thanks for your offer, but I think it's best for me to read into theory right now. I will definitely pick up a book sometime later!
Pick up a book sometime later? Hmmmmm. Then you will only improve sometime later. Sorry, no quick and easy shortcuts in chess. Just hard work- including reading and seriously studying in chess.
Chess in not like some video game where if you just keep playing and trying you will Crack the levels.
Ratings are based upon beating other human players that are all struggling to improve their results and their ratings.
Time does not automatically assure anything.
"... One of the first chess books I ever acquired was Irving Chernev’s The Most Instructive Games of Chess Ever Played. This collection of striking positional games proved to be not only a great source of pleasure, but also an excellent initiation into many of the basic elements of positional play. Unfortunately, the book was published in 1966 and although it is still available and remains in many ways a valuable piece of work, it does now appear rather dated. ..." - FM Steve Giddins (2006)
https://web.archive.org/web/20140708100833/http://www.chesscafe.com/text/review534.pdf

No other way to learn chess but to learn endgame...I Invite you to watch and learn my YouTube Chess Channel...its free to subscribe......FM Jesse
www.youtube.com/channel/UC19el2OO2z-aWnLlyuu8ToQ
Cheers...I hope my YouTube Chess Channel would be of help to improve your chess skills to attain much higher rating....kindly subscribe its free...just press click....FM Jesse

You are very probably making the same mistakes over and over and over again. Find out what mistakes you keep repeating and your game will improve fairly quickly.
"... The game might be divided into three parts, i.e.:- 1. The opening. 2. The middle-game. 3. The end-game. There is one thing you must strive for, to be equally efficient in the three parts. Whether you are a strong or a weak player, you should try to be of equal strength in the three parts. ..." - Capablanca