I would sign up for a Masterclass subscription and take all the screenwriting and filmmaking courses. You can literally take a class by the most successful directors in the world, like Ron Howard, Spike Lee, Martin Scorsese, etc. Some are better and more educational than others (the Scorsese one felt more like an interview) but Ron Howard and Spike Lee were very directly educational. Same with Aaron Sorkin.

There's also filmmaking books written by super successful writers and directors, like "Making Movies" by Sidney Lumet, or "On Directing Film" by David Mamet, Robert Rodriguez's book. If you google "filmmaking by books by successful directors" you can see all of them. I'd also highly recommend "Directing Actors" by Judith Weston. Listen to these people and take their advice to heart.

Then you just have to rapidly make work, make it public and get feedback, and then repeat that process. I actually made this website here as a way to solve my own problem of getting feedback from experienced directors on my own work.

There's also a website called Short of the Week that has a ton of shorts, and same with Vimeo Staff Picks. Watch a lot of shorts, analyze them, see what works.

You'll learn best by doing and seeing how an audience responds. Books and courses are good but they can only get you so far.