If you are thinking about writing a book or have started one already, one of the major issues that you will confront is how to create great characters that come across as fully three-dimensional and credible to your potential readership. The fact that you are writing or proposing to write means that you already possess some knowledge in this area, but it is never hurtful to your project to take on board other writers ideas. Bearing that in mind, the first point I would make is this.
1. Read as much as you can but try not to get bogged down in a 'How to' culture. Advice and tips are useful to your cause, as I have personally found them useful, but at some point you need to put everything on the shelf and have the confidence to start typing. If I could recommend one great book it is 'The Art of Dramatic writing' by Lajos Egri. It's a brilliant work and will give you another string to your bow. You do not actually need to read a ream of material. Many books are designed for commercial reasons and will not necessarily help you to achieve the full three-dimensionality of character that you are looking for. Shorter, focused articles like this one will.
2. Use people you have observed/met in real life. I would not recommend writing characters based directly on friends and family. People you have met and spent time with; people who have been enemies, false-friends and acquaintances are all ideal building blocks for great characters. As a writer you are hopefully a fascinated observer of the human condition. Fiction is not real life, but the closer to real life that it reads (assuming you are not working in a fantasy genre) the better.
A technique I use is to amalgamate several people from real life into one fictional character, giving the character a new name. This gives you the freedom to expand the character into a truly unique person, who is inspired by real life, but well able to dominate his/her fictional landscape. Remember that you have to separate reality from fiction - using a real person down to the last nuance of their soul can work in some circumstances but I would not recommend it. Let the fictional character live and breath on his/her own terms in the world of the story. Even if they are based on a real person, this will give you freedom to let the character live and guide you through the writing process. Once you have started to write your character and they have come fully alive in your mind, you are up and running because now he/she is in a position to exist on his/her own terms, which leads nicely onto:
3. Let the character take control. Let him/her talk to you, tell you what's on their mind. Have a dialogue with the character, ask them questions, listen to what they want. This is a brilliant technique to use, because you are utilizing areas of your brain that you might never have used before. It takes strong focus and serious effort to inhabit the world you are writing about, but you must do it.
The more you believe that you are writing about a 'real' person, while at the same time maintaining control of your new fictional world, the better for you. In effect you are creating a place that is neither fully in the real world nor fully in your own head - I call this the writing dimension - it is a world separate from reality whilst also being partly separate from your own imagination. Once you tap into this space, your characters will be fully three-dimensional and not 100% in your control. Although you have created them and know them up to a point, they will still be in a position to surprise you. And is that not what storytelling and real life is about? Surprise. Once your characters start surprising you, doing things that even you did not imagine, then you are experiencing the true magic of writing.
4. Become completely immersed in the writing process and you will be rewarded for your dedication. You must be able to strongly visualize the world of your story and the characters who populate it.
Amalgamate several real people into one new character and get to know that character well enough to start off your writing, but expect your first draft to be exploratory and completely free. After some hard work, your character will start to live and breathe and surprise you by their actions.
Alex Jenson, 34.