outside of the usual "draw every day until you get in the habit" line i would suggest that you try to set goals for yourself in the form of "completed" pieces of artwork that you can tackle in a day or two. they don't have to be mechanically complex or particularly sophisticated (in fact when you're just starting out they probably won't be) but you'll get a broad scope of what you're good at and what you want to improve on, especially once you've mustered up enough of a portfolio where you can see your skills developing overtime. doodling for the sake of doodling and drawing the same body part over and over as practice never really came naturally to me and i find most of my progress comes from applying all the little facets of art at once (anatomy, shading, etc) because it is all of equal importance to me. of course you can study specific things you want to improve on, but if you're wanting to do big, sort of extravagant things, maybe attempt to incorporate what you want to focus on into a full-fledged piece of art. there are a lot of things to appreciate about one illustration and a lot to learn in the process.

i watched a video once about a bunny who competes in agility competitions, running obstacle courses and hopping over hurdles and stuff. the interviewer asked the bunny's handler how often she practiced. the handler said "almost never. she only practices when she competes." i think that's a good way to describe my approach to developing my skill in art. take my advice with a grain of salt though because my brain might just be weird

also draw every day until you get in the habit