Here is an article by Frank Drouzas outlining what readers look for in characters.
1) A SNAPSHOT CAN STICK
Some writers simply list a character’s age upon introduction, but this tells us precious little and is, frankly, a boring cop-out. (It’s as imaginative as naming your Pekingese poodle ‘Dog’ or calling your wife ‘Mate-Woman.’) Strive to make the character memorable with a clear, candid snapshot. Example:
MANLEY, 23, with a shaggy mop of orange hair and a face infested with freckles, plops down on his threadbare couch and opens up the racing form.
At the end of the bar stands ZOE, Amazonian blonde with creamy white skin squeezed into a black vinyl corset and pencil skirt.
Any problem visualizing these two? Didn’t think so. Images like these should stick to a reader’s mind like cooked spaghetti to a wall. And it’s unlikely he’ll confuse them with other characters he meets in pages to come.
2) CHARACTERIZE IN 3D
Consider giving your characters something extra in the sense of description. That is, not just mere physical traits, but three dimensional ones. MARLA, 52, sits primly with her hands folded on her lap. She looks as though she’s never stayed up past ten o’clock in her life .
ZACK, who’s probably missed several hundred meals since birth, nibbles on a radish.
BANFORD, a bespectacled man who just looks like he’s read all 51 volumes of the Harvard classics for fun.
You get the idea. The reader will visualize them in his own way with these descriptions, and they certainly add color. Note that you’re not actually stating something the character has done that doesn’t play out onscreen. Get around that by using disclaimers like “he looks as though…” or “might have…” or “he’s probably…”
3) TO LIST OR NOT TO LIST?
Some writers feel compelled to include a character list–I see this especially with TV scripts. Intro each character naturally in the story and let us meet them just as we would seeing them onscreen. Above all, don’t expect the reader to pore over every character on the list then have to remember them and their relationships to each other in the script. That’s not to say you can’t include such a list if you want, provided you intro the characters within the script anyway, but the reader wants to dive right into the story. Presenting him with a list of players seems redundant.
4) GRAY CAN BE A GOOD COLOR
Black and white characters belong in the black and white films of the 1910s. The dastardly villains, the white hat-wearing heroes, and of course the damsels in distress. Very cut and dried, very black and white. Consider giving your hero flaws that may or may not prove his undoing. The fact that he has them already makes him that much more interesting to the reader.
5) DON’T MAKE YOUR HEROES PEOPLE WE WANT TO SLAP
“How stupid does he think we are?” I’m sure you’re muttering.
But you’d be surprised. I’ve seen many main characters who constantly irk others and crack wise for 120 pages, and all this just makes them seem, well, annoying. Consequently, they are not the types the readers like to root for.
There’s nothing wrong with a irascible characters going through transformations, but if they just constantly bug the bejeezus out of everyone around them with their smarminess and/or lame jokes, they become hard to sympathize with.
6) LET THEIR ACTIONS SPEAK
Is your character the type to wipe his nose on his sleeve? Plod across the room? Belch loudly in a crowded restaurant, or in a church confessional? Be creative in describing characters’ actions, as this goes a long way in bringing the action and the characters to life in the reader’s mind.
7) EASY ON THE ALLUSIONS
Avoid doing things like describing your character as a ‘cross between Holden Caulfield and Hank Chinasky’ or a ‘female Atticus Finch.’ For one thing, it’s a risky game to assume everyone has read or seen the works to which you allude. (I once read a script profusely sprinkled with several nods to literature and classic films, and I must say, it felt like the writer was trying hard to show off his Liberal Arts degree.)
Literary characters like these are complex, and they should hardly be used to sum up your characters. Besides, why dip your brush in someone else’s palette to color your own work? Paint an intriguing picture of your character and let us be drawn into his story. Don’t look for a ready-made icon to explain him.
8) DO NOT SPARE THE CHANGE
Your principal characters MUST change in some way by story’s end. This is iron clad. It can happen in a big way or a subtle way, but make no mistake it must happen. If there’s no apparent growth, then the reader will feel like he’s wasted his time, something you NEVER want him to feel regarding your work.