[header] How to create realistic fantasy characters [title] Describe your character's physical appearance. [step] You want your reader to create an image of what your character looks like in their mind. Use a lot of detail when determining your character's appearance, and use physical descriptors that also indicate something about your character's personality. 
[substeps] For example, instead of saying, " he had red hair, " say " he had unkempt red hair that looked as if he'd cut it himself. " in the latter, we know that his hair is messy and uneven from a bad haircut.