Surpassing 400-500 elo

I cant get past the 400-500 elo mark, i feel that i struggle with making moves to quickly and the opening, could i please get some tips?

Play 15|10 time control and use all your time before move 30 and finish the game on increment.
Blunder check before you move.
In the opening develop your pieces into play towards the center.
Lasker formulated 4 common sense opening principles:

1. Only play your e- and d-pawns.
2. Play your knights before you play your bishops.
3. Do not move the same piece twice.
4. Do not pin your opponent's king's knight with your queen's bishop before your opponent has castled O-O.

The reason your stuck in Low Elo is because of your Openings my man!

You should be playing that Aggressive Stuff!

i used to play random openings when under 800 and still win. you only need the basic principles like control the center, castling as quickly as possible and connecting the rooks..etc. the problem with lower elo range is the inconsistent move quality they make, sometimes they make good moves then a blunder the next. my tip to get out of the lower elo range is to just keep a consistent move quality, you don't need to make magnus carlsen level moves, just make a regular normal safe move that is not a blunder. as long as you're consistent and surviving move by move without a blunder, the opponent would eventually blunder in time and that is when you punish him.

Improving Your Chess - Resources for Beginners and Beyond.....

https://www.chess.com/blog/RussBell/improving-your-chess-resources-for-beginners-and-beyond

500

Plays slowly(play rapid) then switch once you have speed

Misses obvious tactics(do puzzles)

Bad opening and patterns(play more games)

Mentality(try to avoid tilt and don't accuse others of cheating instead enjoy the game)

If you don't improve that's ok not everyone has to be good at chess