I can't stress enough on this one, the paper should be as good as the drawing itself. If you embark on drawing an object like an eye, the subject matter should reflect skill and understanding of perspective.
Just like any other form of art, drawing triggers emotion in an artist, hence the emotions should pass on to the viewer. It is important to keep in mind the triggers you want a person viewing the art to feel. Natural Science rules apply to congnitive behavior and perception. The light should have meaning and reflection should adhere to the angle of the object.
Let me simplify this, when an artist draws an object on a paper, there is a sense of effort and desire to do so, hence the artist should try in it's simplest form to pass that emotion to an end user. In retrospect, the user or the viewer then receives somewhat same emotions like that of an artist.
With that, it is important to choose the right subject that objectively reacquires meaning for a long term value. Once the skill is mastered, the sky's the limit. Moreover, Art is impeccable, it is surely flawless at different levels. There is no bad art, every drawing or painting has its own meaning, no matter how close it is to realism.
When embarking on a new drawing, it is important to have a plan in mind. How you will execute that plan depends on time at hand. Drawing is just like Software Development, allow sessions of time to pass in between for fresh eyes to catch the mistakes you made previously. Having an observatory eye is crucial to producing a masterpiece. Every professional has their own set of tools they use to accomplish tasks, it is, therefore, important to know what tools works for you. This includes knowing papers that are intended for the different art style. If you are a beginner and you want to draw a realistic eye, it is important to be aware of different paper texture.
For example, when I started drawing an eye, I decided to draw on a Bristol Vellum Strathmore paper because of its two different surfaces. One surface or side of a paper has a smooth touch and the other is kind of rough, the rough side is good for drawing textured figures like an Orange, a dog’s nose or a rock while the other smooth side is good for drawing figures/objects like portraits, flowers, baby faces, and many others.