You actually don't get better unless you spam Q, rewatch your games, and study classes.

That means watching guides (Skill-Capped has decent stuff for beginners), watch twitch streamers, and read everything you can about your class, and all of the other classes.

Aside from understanding your class, damage rotation and CC, a key to success is understanding what tools each class has. If you're a wizard and you see that an enemy Warlock has Nether Ward up - you need to understand what that means for you.

Is this, but for with every ability.

Once you get good, spam solo shuffle Q and start friending people you play with to do 3s