A good writer makes characters sympathetic, well-rounded, or complex even though the writer may not be like the character or even like him or his beliefs. This allows for a sense or realism.
You have to reveal some basic facts to the reader about a character. The reader should know the following things about a character: appearance, age, gender, educational level, vocation or occupation, financial status, marital status, hobbies, religious beliefs, ambitions, motivations, etc.
A good writer is able to reveal all of the above by giving the readers clues and hints. Never should a writer directly disclose info. This makes the story sound childish and boring.