The 3 most important things to learn about how to draw is Dexterity, Observation/Analytical skills, and understanding Perspective
Dexterity/Gesture - you need to learn how to use your shoulder, how to make clean and elegant strokes, straight lines, and make near perfect circles. I would tie gesture in this category as well.
No matter what your goal is this is the most important thing you should practice. Its also not something you can just learn and understand, it takes training your muscle memory nearly daily.
While you're doing this you should also practice regular figure drawing, to practice gesture. Figure Drawing goes a long and you just get better at it the more you do it and the more you learn in fundies
Observation/Analytical - You need to be able to see like an artist. Make accurate measurements, see angles, see shape and size relationships and see value and color like an artist. Thats your observational skills, but analytical skills are related but different. Its being able to take from things you like and learn how to design like them. You don't need to become a photocopier, but regularly training your eye helps you in your studies and design work.
Perspective - Never doubt how important this skill is, there is a reason why European art spikes so high up after its discovery. Nearly every fundamental builds off perspective and its the easiest fundemental to actually master. Although it is likely you won't be using most perspective concepts in your work regularly, it is incredibly important to actually understand and sketch it.
And of course, also do your own imagination drawing and style studies whenever you want. Taking your studies and actually incorporating in your work shows that you understand it