So I didn't know what to draw, so I redrew this Percy Jackson fan art from 2013:

*shudders*

(I liked drawing them as wolves)

Young artists, please invest some time in anatomy. Drawing from life is especially important. Understand how bodies, muscles, bones and ligaments work together. And draw things that are out of your comfort zone: it will help your anatomy, surprisingly. (Ex: drawing a human will help you draw cats faster because humans are more difficult and have more muscles and blah blah blah)

Digital artists especially (but this applies to all artists who use color), choose colors that look nice. Meaning not saturated too much, or are to gray and muddy. Color schemes or pre-chosen pallets of colors are useful as well to keep your colors in check. This is important for digital artists because they have literally every color and shade imaginable, and it's hard to know which colors don't look gawky or ugly.

And finally, just draw. Every. Freaking. Day. I didn't improve this much over five years by just leisurely drawing. I had to practice, and practice effectively, meaning I went out of my comfort zone and did stupid art exercises. But have fun, too. If you don't have fun, then what's the point in doing art (or anything, to be honest)? Art isn't a job/hobby that pays well, no way Jose, but if you make it fun, it will be more than worth it.