SIMPLE TRICKS FOR CREATING THREE-DIMENSIONAL CHARACTERS
First, what is a three-dimensional character? Easy. It's a character who seems/feels real. You know a three-dimensional character when you read him or her. You care about the character, love the character (or love to hate the character), are fascinated by the character and, most importantly, you're still thinking about that character long after the book ends. Why are there so many modern retellings and reboots and reimaginings of Sherlock Holmes? Because Sir Arthur Conan Doyle made Watson and Holmes so lifelike that 221B Baker Street still receives mail and offers from women asking to be their new housekeeper. How does Doyle accomplish this feat, this miracle of creating flesh from paper? How does any writer turn black marks on white paper into a living, breathing person? The answer is simple, and it come from Oscar Wilde.
Every saint has a past and every sinner a future.
There's your answer to three-dimensional characters in one pithy statement. If you want 3D characters they must have memories of their past and dreams of their future.
Every saint has a past.
Replace "saint" with "main character" and now we're cooking with gas.
As long as your character is school-aged or older, he or she has a past they remember. And just like you and me, they remember it often. Someone asked me today if I knew our mutual college friends, now married were expecting twins? I didn't, but as soon as their names were mentioned, I recalled a dozen memories of those two from our school days before they were a couple.
Memories are like spice, they give flavor to your characters. Bitter memories help you create a bitter character. Joyful memories create a sweet character. Ask yourself what flavor your main character is and you'll know what type of memories to use to season your book.
A memory can reveal an aspect of your character that would surprise the other characters if it were revealed. An older quiet librarian can see a handsome patron and be reminded of a holiday in Jamaica when she had a passionate affair with an islander twenty years her junior. Suddenly the reader knows this apparently stuffy librarian has a wild side.
Every sinner has a future.
Again, replace "sinner" with "main character" and you'll get my point. Everyone dreams of the future. Perhaps it's a fairy tale fantasy of someone rich sweeping you off your feet and into the lap of luxury. A reasonable fantasy would show that this character is level-headed and practical. A fairy-tale fantasy would show us the character dreams big.
I'm moving to a new city in a few months. Not a day passes that I don't wonder what my new life in this new city will be like.
Your characters gain depth when you give them hopes and dreams. If the dreams are impossible, the character seems pitiable (Walter Mitty). If the dream is possible but will take a lot of work, you give your character a goal and motivation to better himself (Pip).
Your point-of-view characters need to seem so real that when they get into trouble, your reader is genuinely worried about them. That worry keeps the reader coming back to the story and finishing the book instead of getting bored by the flat portrayals of stiff cardboard cut-outs you find so often in genre fiction.
Here's a lazy way to give your characters dimension.
Go through your draft. In every long scene make sure your point-of-view character either remembers something from the past or dreams of something about the future. Don't overdo it. Too many memories and fantasies can slow the action down. Sometimes you only need a single sentence here and there or a short flashback.
Use memories and fantasies judiciously and your flat characters will soon be leaping off the page, grabbing your reader, and dragging her into your story. And isn't that what every writer and every reader wants? And the best part is you don't even have to get off the couch to employ this technique. All the memories and fantasies your characters need are already in your head!