When you get better acquainted with your creations, you will hold your readers' interest, too.
Some writers hate to have too clear an idea of the story they are telling, and the characters they are creating, when they first sit down to write. They prefer to see where the story and the characters take them. Other writers, however, have to know exactly what will happen, and who each character is, in as much detail as possible, before beginning the journey.
Although each style has its strengths, and weaknesses, the first kind of writer may benefit from creating a character sheet that asks and answers some basic questions, such as a character’s age. After all, a police detective who is 45 at the beginning of the book, and, twenty pages and a day later, has suddenly aged to 53 is the type of blunder that doesn’t sit well with editors, or with readers.
Create character sheets in a working journal specifically for the story you are going to tell, or make a computer template, into which you can key the answers. Save those sheets on your computer or print copies of them to add to your working journal.
Start with basic questions like these: What is your full name? How old are you? Where were you born? When were you born? Where were you raised? What are your parents’ and siblings’ names?
Then move on to questions such as: What do you eat? What is your favourite food? What is your favourite drink? How do you spend your Saturday nights? Do you read? What kind of books? Do you watch television? What is your favourite show? Do you listen to music? What kind?
Go into more detail here: Are you married? Divorced? Do you have children? What are their names and ages? What is your job? What do you like about it? What do you hate about it? What do you spend your money on? Do you travel? Where and why (or why not)? What does a typical day in your life consist of?
You can also create a physical description of your characters with questions about eye and hair colour, height, weight, scars, physical or mental challenges. Remember that a character sheet can be as general or as detailed as you require.
The answers your characters give to the questions you ask will provide a place to start in building believable characters. You can add more flesh and blood to each sheet or just stay with the skeletal outline, whichever works best for you.