How do I increase my ELO rating?
More Rapid, less Bullet. Use Rapid for learning, Bullet for fun and for testing your knowledge.
Play through EVERY game you lose, and make sure you understand WHY you lost that particular game. Yes, I know that looking at your losses is unpleasant. Do you want to improve your chess, or do you want to stay in your comfort zone and not improve? Your choice.
Don't bother studying openings until you are around 1500. Spend that time on something useful instead, like studying tactics, endgames or model mates.
Play over annotated games by the old masters, from (nearly) 100 years ago... Anderssen, Morphy, Steinitz, Tarrasch, Chigorin, Nimzovich, Breyer, Reti, Alekhine... stop somewhere around Botvinnik. You'll find their style of play much easier to understand than a game by Carlsen, Nakamura or Kasparov.