Studying anatomy can -- and does, in my experience, make a huge difference! Look at the figure drawings of some of the greatest artists -- Leonardo, Michelangelo, Rembrandt, Picasso. (Check out Rembrandt's many self-portraits too.) If you know at least rudimentarily how the skeleton and muscles work under the skin, you'll better understand the superficial (surface) appearance, Eyes sit in sockets; there's a bridge to the nose, etc.
And, as you have noted, practice is essential.
Since you can draw things "in front of" you, get a mirror -- or sit in front of one -- and draw yourself. Pay attention to what you SEE in the mirror, not what you "think" you see in your head. One of the big pitfalls of neophyte artists is not really looking at and studying the subject but rather drawing from "memory". Once you have confidently created some realistic drawings, then you can let loose your imagination. (It's the old you gotta crawl before you walk, walk before you run adage.)
Copy problems are also excellent practice. Take a color photo and render it in black and white (with all those shades of gray in between). Copy great artworks and try to figure out how the particular artist decided what to emphasize, how to compose the piece, etc.
Go look at great art (in museums, exhibitions and/ or online). Eventually you'll develop your own style. In the meantime, learn from the greats.