Stuck at [300-400] ELO—how do I improve?


You have not been following the developing principle well

It's mostly about following key principles when playing. That approach helped me reach a 2000+ rating, and I teach others to do the same. You can learn them yourself as well. Here's an example of some chess principles: https://www.chess.com/article/view/principles-of-chess

Maybe attending a Local Chess Club, where they can help you grow in chess, aswell as building up OTB experience

If you want some games reviewed i could also help you with that, I am 1750 Elo in the Rapid games and have been playing for 5 Months now

Also in my own Club there is alot of usefull information to be found within various Topics,
Link to my Chess Club--> https://www.chess.com/club/chess-fiends-and-addicts

Thank you for this information!!!
No Problem, My Goal is to help others improve their Chess Skills
A good idea would be some sort of a plan. "A bad plan is better than no plan at all". A plan for growth, and a plan for the game. Your game plan should lead you to positions in which you are comfortable. I would put opening study at the bottom of the list. If you "work you study bsackwards" a la Capablanca in Chess fundamentals. Also, one can use different websites for different reasons. I use chess.com more for the social aspect, lichess is my sandbox, laychess for serious real-time play, and also FRITZ and Chessbase online .and for "thematic" correspondence chessworld.net
I am 50+ years in the game, but never played a FIDE rated game, I did my time with OTB tournaments for 30 years starting in 1973