Make him honest. I don't mean 'never fish for spare change in a pay phone honest.' I mean 'tell it like it is and own up to it' honest. Readers will forgive a character for any number of flaws if the character is honest about who he is and what he's doing. - K.M. Weiland

Think of your main characters as dinner guests. Would your friends want to spend ten hours with the characters you’ve created? Your characters can be loveable, or they can be evil, but they’d better be compelling. ― Po Bronson