Do a lot of puzzles, always review your game at the end and look at the mistakes you made or moves you could have done and look at video online for tips. Also learn openings and endgames.
Road to 1200

complete all lessons, and then play about '10' 10 min games. you probably cant be defeated coz you have done all lessons. i used a shorter version of this trick and went from 500 to 700 elo in 1 week.
Honestly try to just play solid chess and take advantage of your opponents bad moves and blunders most of your opponents will blunder by move 10-16 so make sure you spot it (not all of them tho)
I could give you longer term advice tho cause this isn't really much of advice
I have a goal. Reach 1200 Elo until Sunday for the first time. I am currently at 1142 Elo. Please give me some tips.