Halivar said:How do you make an interesting character with a low charisma? Are your characters just ugly, or do they have a serious social problem? Did I pick the wrong stat? What's your typical dump-stat, and how do you roleplay it?
As others have noted, a 7 isn't really particularly bad. It's a -2 modifier. Consider that the character was probably not gong to be spending on social skills anyway (between them being cross-class and him getting few skill points each level anyway). Early on, it might seem a big deal, but as time goes on, the skill points become more important than the modifiers - relatively speaking, he'd be abysmal at those skills even if he had a positive modifier.
In such a case, I would not go out of my way to play his charisma as really particularly bad - I'd simply avoid playing him as if it were particularly good. A bit socially inept, a tendency to be rude or make social faux pas, perhaps. How you play it would depend on the rest of the character concept.