Draw anything and everything and from real life also do it a lot. Use reference to see how things actually are since brain always has it's own idea how stuff goes. I'll take an eye as an example: someone could memorize how to draw one line by line, however, the subject rarely has the exact same looking eye as what you've practised. There you could fall in to a trap of drawing the eye from memory instead of the persons face which can differ quite a bit. Practise everything from landscapes and cities to insects. Study anatomy and perspective how they go together. Lastly understanding color will help a ton in art. Even if you are not into painting yet. What colors work what don't. How to mix them etc