Have you ever sat back and wondered why people can out shoot your two thousand dollar DSLR with a phone? It’s probably because you aren’t taking the time or putting thought into getting your composition down. Right off the bat let me say that people who mastered the rule of thirds early are the best at knowing when to break that rule.
The best way to improve your composition skills are to slow down when shooting, and start off shooting something in your environment, something you see everyday and know what it looks like inside and out. For example, every morning take a photo of the same coffee cup, and every time you do it make sure the coffee cup is in a different spot in the frame. After five days pick your favorite one and I would wager that without you knowing or trying it will satisfy the rule of thirds in some way.
My composition is solely based on leading and dividing lines, and because of this, leads to some interesting rule of thirds breaks. I will put some sample images with my drawings on them to attempt to explain them better, but in my experience once people see my rationale, it changes their experience with all of my content usually for the better. I found my composition, and my eye after just shooting without a goal and getting a lot of reps with no-one watching (not that anyone is watching now). Once I found it, it makes shooting fun and experimenting easy because I have a base and a knowledge to work off of.
If you don’t think you can learn well from books and youtube on your own do not be afraid to take a class from a photographer near you at a school or studio. I learned from an amazing teacher in high school that changed my life and put me on the trajectory I am on now. I am absolutely still learning and not perfect, but that is a base I always revert back to when I need to get back on track.
Seek the basic knowledge, master it, and once you’ve got it break it in interesting ways.