Chess improvement

Confession: I have given up on any serious effort to improve my chess. However, six months ago I discovered the joys of atomic chess and my enthusiasm shot up again. I felt motivated to become good at this variant of chess. After about seven weeks of playing intensively every day, I raised my rating from 1500 to 1950, where it has stayed, with ups and downs, for the last six months. How to get off the plateau? After a lot of thinking about how to improve, here are my conclusions:

1) Learn the killer openings of atomic chess and how to survive them. Use Stockfish for this.
2) Use Stockfish to analyse every game I lose.
3) Be rigorous about performing an error check before every move. Especially check whether the opponent is targeting a pawn next to my king, and never more so than if I am one move away from executing mate.
4) Practise prophylaxis, especially as black, who is always on the back foot in atomic. Always think about how my opponent can breach my position, including by means of a sacrifice or two.
5) Once into the late middle game, open files for rooks become crucially important, much more so than material balance. Do not win material at the cost of exposing my king to a rook. A rook that is free to attack my king usually wins, or at least forces a draw.

Are these factors relevant to improving at classical chess, you ask? I think that nearly all apply to standard chess, with variations.

1) To be good at chess one needs to have some knowledge of openings, though this is much less important than in atomic chess, where in most openings, black loses if they make the wrong first move.
2) Analysis of every lost game is a boon.
3) Error checking before making a move is life-saving.
4) Prophylaxis is important at every level of classical chess.