Two tips:
Draw more and use models
Drawing more makes you better, just how studying more makes u smarter
Using models when drawing makes drawing that thing easier. Using a picture of something as a model for drawing always helps.
to add onto this, drawing from models means the real thing. not very reliable to use someone else's interpretation of an object when you can sample right from an object. its just like primary source and secondary source in history: the secondary source gives their take on a primary source, and so should you
looking at how said things work (anatomy for living, mechanical design and structure for nonliving, even how nonorganic natural things get their shapes) is very helpful. even researching the science behind something is at least a little beneficial
and despite how school seems to teach, its perfectly ok to take your time on art. put effort into everything in the piece and dont cut corners
the elements of art and principles of design are actually more important than you might think, so doing some digging about those will compliment everything else you master