There's probably a continuum between total free-form and total dice mechanics. Think about where on that continuum your group is at, think about where you're at, and think about where you'd like both to be. how might you adjust on both sides to meet at a happy middle?
For example, somewhere on the continuum between freeform and rolling there's probably figuring out what you want to say more than rolling a skill, and then rolling it to see how you say it (phrasing, eloquence etc.) So that if you slip or stammer, the important thing is coming up with a good idea to convince, persuade, or intimidate whomever you're talking to. Sense Motive and doing your homework (researching your target in other ways like looking through archives, searching through homes, etc.) might help inform you about what your target might react to or want to hear.