So anyway, let's assume that we are designing/doing concept art for a 3rd pov game. So, we have to design at least one playable character or race. The game concept or story may have already described to some extent what the player/race should look like. And often these descriptions, which have not been written by an artist, are more puzzling than helpful. ;)
For example, this week I was trying out for the position of concept designer for an RPG. I was asked to design, as my sample, a race of fish people. Now, this was a playable race. When designing a playable race it is important to make it attractive in some way so that players will want to have an avatar of that race. But there are different ways in which something can be attractive: it can be cute, graceful, intimidating, powerful, pitiable, curvaceous, enigmatic, threatening, placid, etc. And different types of visual attractiveness appeal to different players. Violent players like deadly looking avatars, pacifist players like cute avatars, and flirtatious players like curvaceous avatars.
The colorscheme also effects the type of player your race/character will appeal to. You can have neon colorschemes, pastel/pearly colorschemes, bold/classic colorschemes, naturalistic colorschemes (browns mostly), gothic/shadowy colorschemes, and jeweltone/rainbow colorschemes. You should chose your colorscheme to match the particular type of attractiveness you are trying for - for example enigmatic charaters or races are usually pastel, sometimes gothic or neon, because these colorschemes are rarely encountered in real life and are generally associated with complex things, but never bold because what's mysterous about colors found in every child's box of crayons, advertisements, maps and signs, and other mundane, simplistic things?
So back to the fish people. The personality of this race was suppsed to be somewhat isolationist and mysterious because, after all, they lived underwater away from the other races. (Note: this is not good from a design perspective, you can get the most interesting combinations and contrasts if you design your world so that your races can get at each other, or better yet are stuck together in an uncomfortably small area.) So, mysterious fish people, which had to be attractive so that players would want to play them, particularly players who already liked the idea of acting isolationist and mysterious. So (after looking at some source images of tropical fish and goldfish) I decided to try to appeal to these players by making the fish people a bit less human looking (fish eyes, no nose, slightly elongated and flexible neck and torso to go with the fishy crest and webbed and clawed hands and feet that had already been specified by the writer.)
Also, there were supposed to be two varieties of this race, a freshwater and a saltwater one, so I planned to give each a unique sort of appeal by giving one flowy goldfish fins and the other spiky lionfish fins, so that the first was more gentle-looking while the second was more dangerous looking, but both, hopefully, were beautiful despite looking a bit alien. I finished up by choosing a pastel base colorscheme with neon highlights, and, low and behold, it did indeed look attractively enigmatic! :)
At least, I thought so. It's generally wise to get a second opinion on these things. My roommate didn't like the fish person, but he also admitted he was biased because he didn't like any fish people except maybe mermaids. I won't get to hear the designer and his team members opinions until the competing concepts by the other artists who want the job are submitted and the team votes on what they like best.
Edit Again: My bid lost. Do you think I succeeded in making it look graceful, beautiful, and enigmatic? Look at the Fish Person. Would you like to play an avatar or flirt with other players/NPCs that looked like this?
Another little anecdote about types of visual appeal and second opinions: the MMORPG I'm doing the clothing design for has some non-human races as well, and recently I was assigned one of them to design clothing for. I took a look at the concept art, and found a long-furred animalistic creature with a lion's mane and a horse's tail, much like Beast from _Beauty and the Beast_ or the Norns from the game series _Creatures_. My first reaction? "Cute! Can I put collars on them and ribbons in their manes and tails? Let's make their coats come in patches and leopard spots and zebra stripes!" The designer's response: "Ack, they're not supposed to be cute! They're supposed to be fierce! They're the bad guys! Like orcs or something." Me: "But orcs are cute, when I played _Warcraft_ I always played the orc side..."
So the moral is, race/character visual design is all about player psychology, and you have to be careful to make sure that a race/character's appearace, culture/personality description, and role in gameplay reinforce each other and are targeted at the type of player you want to be interested in them.