Then comes the research. I usually hit up Google images, or various magazines and reference books I own to compile an image bible for each issue. I keep that with my script as I work through the book so I have it handy whenever I come to that particular scene where I need to make specific things look.... well...specific.
Here in Snake Eyes #1, for instance, I have never gone mountain climbing. I've done it indoors or repelled a few times. But obviously nothing to this extent growing up in Illinois where the highest elevation is the quesadilla I just dropped on the ground. Hence the research.
Or in this case, for the Savage Sword anthology for Dark Horse comics I had to draw a convincing 15th century France. Convincing being the key word. I'm not an expert, or even incredibly educated on the subjects I research out by simply compiling photos. But I like my work to seem real enough that it's a believable scene, and a believable environment. That means I need at least a base knowledge of how things look and work to convey it properly.
That also means that when I have to make something up and fill a space with a combination of real objects and fictional items, they look believable together.
Stark Industries (Iron Man)
Village in the Mountains (Forgotten Realms)
The PITT (GI Joe)