Need help

Hey everyone. I know this is a weird, open-ended question to ask, but...how exactly do I..get better? Everyone says "play a lot, study a lot" but I feel like I'm just not doing it correctly. I feel like I play the same few openings on white and the same few defenses on black depending on the situation, and I feel like my growth as a player has just been really slow and I'm not sure if that's on me or because it's harder to go up the higher your rating gets?

I'm a Class D player (1366) and my life goal is to be able to hit Master. At any point in my life. I try going to tournaments whenever I can, and I mostly play chess on my phone (Chess for Android and chess.com tactics + a tactics app on my phone) every day, as being able to actually sit down with people regularly is difficult with working and everything.

I just really want to know if I'm doing something wrong here, if maybe I do actually have a limit that I shouldn't try to surpass, or maybe that I'm actually on the right track? There's always room for improvement and I feel in the dark about how to really make myself better as a player, both in terms of actual skill and in rating.

I know this is probably a very naïve question for me to ask, but I don't really know how better to phrase it. Chess has and will always be a passion for me, and I want to be as good as I possibly can. Any help would be more than welcome.

Thank you.

Tactics...tactics..tactics...

Find 2 openings to play for white,, and black.  Study, and learn the ideas, and principles nehind those openings.