There is an adage among writers that goes, “Write what you know.” This statement is interpreted to mean that an author’s work will make a stronger connection with people when the author writes things that are familiar to them. Of course, only writing about things that the author has experienced would basically eliminate the entire science fiction and fantasy genre that we love so much. In the end, a great work of fiction needs to come from the imagination, but also needs to be backed up by research and infused with the characterizations and emotions that the author has experienced. This is what makes a work really resound with the audience.
How does this apply to illustration? When it comes down to it, artists and authors are not all that different. We are all “creating our own worlds,” in a sense. If this is true, then perhaps the old adage heard so frequently by writers should be heeded by artists as well.
Disney concept artist Chris Oatley once recorded a podcast discussing his quote, “If you understand the form, you can paint and draw the form.” This idea is critical when it comes to creating good science fiction and fantasy illustrations and concept art. Although the thing you are trying to render may be coming from your imagination, it needs to be backed up by reality in order to be believable. While we may not actually be able to study dragons or futuristic spacecraft, we can learn about the anatomy of a lizard, how wings work, and the propulsion systems used today. This can take time, but the concepts in your art will be so much stronger when you understand the science behind the form.
Learn to draw from reality. Use references. The world you have created will really come to life when you draw what you know.