I thought I would take a bit and just put down some thoughts on how best to describe your characters in order to get the best images back from artists like myself.
A little side note here: don’t feel like you have to write War and Peace for each of these elements – a few words will do. It’s even reasonable to leave some blanks if that’s how you’re feeling (like maybe they don’t have any distinguishing marks) but the more of these elements you comment on, the more ‘accurate’ your portrait is likely to be!
General Setting
To background or not to background – that is the question. If you would like your image to have a background, let the artist know. Just be aware that many artists require additional fees for the addition of background elements. It does, after all, take a good deal more time to do a full scene that a single character standing by themselves.
Periphery
Companions
Is your character part of a party? Going solo? Maybe they’re hiding in the crowd?
Critters
From the horse they ride to the old standard of a wolf companion, there’s a lot of animals associated with characters in the worlds of fantasy and science fiction. Leave yours out of the description, and it may feel a bit like something’s missing.
Physique
Age
At first, this would seem kinda obvious, but I feel like I should point out that while some folks in some settings can live for hundreds of years, we mortal humans can only manage about a century in our current medically advanced age.
What I mean is: be sure that (whether in this section or in another) you make it clear to the artist if the age is not commensurate with their appearance. Maybe they’re 100, but they look like the human equivalent of twenty five (lucky bastitches). Or, maybe they’re fifteen, but look like they have one foot in the grave.
Age is important, but since we’re talking about illustration, it’s the character’s apparent age that’s critical.
Body Type
Hair / Head
Distinguishing Marks / Unusual Features
Attitude / Emotion
Emotional Display
Posture
Pose / Position
Costume / Gear
Quality / Status
General Theme
Color Theme