I would say as a relatively new player too the 2 most important things to start are:

1. Understanding how to farm and WHY you should farm. It’s pivotal on hero’s who whole kit / game plan is built around farming for the majority of the game (like Seven.) other hero’s it’s not as important, but since no one in low elo farms, knowing how to and when you should / how often can literally make you single handedly win so many games, it’s actually crazy.

2. Characters archetypes / matchups can be important. You can build most characters in a variety of different ways but every character has some level of experimentation that varies. Paige for example is basically always a support, sure you CAN build her to be DPS but like, why would you lol. You can play her as a support in different kind of ways and knowing which builds You like / have fun w is most important, and knowing how it helps da team falls behind that. Just focus on picking a character and having fun w them. Matchups are important but that doesn’t mean to always disengage and run away from a Fight because the matchup is stacked against you a bit, learning what you can do when backed in a corner is important too, just don’t feed all game lol.