I most often use a formulaic set of questions to develop my character. I decide what type of creature the character is first – a human, a rat, a dragon, a goblin – and then I give the character a name, which often defines them in part either physically or emotionally, e.g. the rats in A Rat Called Twelve all have nicknames like Spex and Freckle that describe something physical about them. My dragons might be named for their colour like the dark blue Midnight; or by their personality like Elphie who has many of the characteristics of my dog, Alfie.
Once I have the character’s look and name in mind, I then ask myself what are the character’s likes and dislikes, what do they want most in the world (physically and emotionally), and why can’t they have it? This set of questions were suggested in an online writing course and have stuck with me. They help me progress the character into his or her story.