Asking what the difference between every 100-200 rating isn't very productive. You just have to increase your understanding of certain concepts, knowledge and ability and that's all it is. You can't pin point it to something specific.
If you have 3 players at your elo all of them can increase by 100-200 rating from different means.
Improve your knowledge of your openings after every game, look at them, it will get you into easier situations that you are more familiar with.
Save the tactics you miss ingame and keep looking at them, daily.
Study the common endgames, especially king/pawn and rook/pawn endgames. Get familiar with opposition.
Feel free to add me as a friend I am always willing to help.
How to get from 1300-1500 in Rapid


Your account started 1800 and declined to 1400... not much of an accomplishment with 73% losses

I would say try winning more games at faster time controls. That's sure to bring about the result you're looking for.

Play Stronger Opposition ( 150 -- 300 rating difference is what I would suggest) As much as you can, anaylse your games. i wouldnt focus, and/or put too much time into Openings until you are at least on the borderline of 1600. even then you dont need or have to memorize tons of variations until youre prollly around 2000. I wouldnt suggest playing more then one opening at the 1300s 1400s 1500s or even 1600s stick to one opening you know and feel you play well with white and vice versa with Black. But most Importlantly Just have Fun.
لو ترجمتم لنا هدانا واياكم الله