I have found that Persuasion success is more likely if you pay attention to the character and figure out which of the options is the most likely to work, instead of just always picking the one you have the highest attribute score in.
I've had a reasonable level of success by doing that.
For instance, Stingtail is not persuaded by a general "if you don't help, people will die", but he IS persuaded by a specific "if you don't help, you, specifically, will die" check.
