Teaching yourself to make art is a lifelong endeavor. Books and courses will help but it’s up to you to keep the work interesting and relevant.
Look for creative ways to keep practicing the basics, like contour drawing, proportions, foreshortening, tone, shading, volume, etc.
Don’t make drills dull. Find ways to mix things up. Draw things that mean something to you.
Instead of setting up artificial subjects like bowls of fruit or vases of flowers, draw the contents of your fridge. Draw the roses you got for your birthday and write about how you feel getting a year older. Instead of drawing naked strangers in a life drawing class, draw your naked spouse, your cat, your boss. Rather than doing “Drapery studies,” draw the shapes your feet make under the covers on a Sunday morning.
Be inventive. Be fresh. Be personal. It’s an adventure, not a chore.