"Is a bit of white paper with black lines on it like a human body?"
One sense that the OED gives to the verb "to draw" is "to make (a picture or representation of an object) by drawing lines." There's something unsatisfactory about the circularity of this definition (it uses the word "drawing" to define the verb "to draw") but I suppose we all know what it means. To draw is to make a picture of an object out of lines, and a picture is a two-dimensional representation of an object (or scene). The lines are important. A photograph, though two-dimensional, is not a drawing, nor is a painting (which makes the picture out of broad and fine strokes rather than lines.)
The status of the "object" in this definition also needs some clarification. After all, it is possible to "draw" a unicorn, so the object in question need not actually exist. You can draw a line or square, too, so it doesn't have to be three-dimensional, though the representation will always be two-dimensional.
For some time, now, I have been trying to get writers to understand their work in similarly straight-forward terms. They have some object in mind, and they want to render it on the surface of the page. Their object is often four-dimensional—a story that unfolds in space and time, for example, or a data set from a time series—but their "picture" (the writing not the drawing) is always one-dimensional. Writing is linear: one word follows another in a sentence. One sentence follows another in a paragraph. Calligrams and other stunts not withstanding, the sense of a piece of writing is whatever emerges from reading the words in an order determined by convention.
Just as the meaning of one line in a drawing depends entirely on the meaning of the lines around it, so, too, do the words in a piece of writing depend on the words around them. Writing and drawing are both arts of arrangement. If you want to master either art, it is worth approaching it in the simplest form first. Consider the problem in terms of "marking up" a piece of white paper, either with two or three pencils of different grades (perhaps also an eraser), or with the letters of the alphabet and basic punctuation marks. (I would include italics among your basic resources for writing, but not boldface.) Imagine the drawing occupying about two thirds of the space of the page (leave a lot of white space) and imagine a paragraph of at least six sentences and at most two-hundred words, in a nice easy-to-read serif font, double-spaced, with no right justification.
The challenge is to render an object or fact accurately in that form and to do so within a manageable amount of time—twenty-seven minutes, for example. If you don't choose something to draw—a hand, a face, an apple, a cup—you won't expect to succeed. The same is true of writing. Choose some fact you know to be true or some event you know has occurred. Then describe it; write it down. It will help you immensely if you choose the fact to write down (or even the object you want to draw) the day before. This will give your subconscious time to prepare.
Once you have made your attempt, step back from it and look at it, or read it out loud. Do you like the way it looks or sounds? Consider again the object or fact or event you were trying to represent. Did you do it justice? Be honest with yourself, but not mean. Don't dwell on it too long. Tomorrow, do it again.