I'm currently planning a space opera webcomic that will focus on two characters, a drifter and a former-family man whose lost almost everyone he's loved. I have some ideas about these character's past and their psychology, but I don't know how to make them sympathetic and likable when their introduced.
From what I've seen, stories usually do this by making the character funny or by by showing the character perform some amazing act of bad-assery or heroism. I don't feel particularly confident in my ability to create humor and these characters aren't bad-asses. Any advice on how to make a character likable from the beginning?
Oh, and just so I don't have to make another thread for this, how would you show that an extroverted character is depressed or grieving without making them less extroverted?