First-time poster here. I apologize if this question is better suited for another sub-forum.

I need a map for my setting (a world map, to be precise). Though I am well-versed in Illustrator and Photoshop, the actual drawing of a map is not my forte. As such, I figured that I'll pay someone to to the drawing for me. But! How far along should I be with designing my setting before I comission a map? Should I have a complete list of cities and other points of interest? Furthermore: I understand that certain elements on a map - like rivers and shores and whatnot - require thought to be "realistic." Can I assume that my artist of choice will take this into account?