I agree with Merc here. If the character is really unredeemable (and I usually take that to mean "no fun to play" - if you're enjoying playing them, then there's no real reason to change), it might be time for the spotlight of your RP to move away from their life. Make a new character (by fantasia/namechanging this one, or an alt, or however you choose) and try something new.
That said, probably the biggest piece of advice I can give is make a character that adds to other people's RP. Lots of people pay attention to their character's motivations and back story and construct all sorts of things that make their character internally consistent and all that. At the end of the day, though, we're looking to RP with other people, and the best way to find that RP is to make sure that your character adds something to their RP. I'm not saying completely dump your own desire for what to play, but I am saying that you want to focus on making sure that the people you're playing with are getting something out of the RP. Think about your character as if they were an extra in someone else's story.
That said, probably the biggest piece of advice I can give is make a character that adds to other people's RP. Lots of people pay attention to their character's motivations and back story and construct all sorts of things that make their character internally consistent and all that. At the end of the day, though, we're looking to RP with other people, and the best way to find that RP is to make sure that your character adds something to their RP. I'm not saying completely dump your own desire for what to play, but I am saying that you want to focus on making sure that the people you're playing with are getting something out of the RP. Think about your character as if they were an extra in someone else's story.
