[quote=@Atrophy]
Meaning if you yourself aren't quick witted and funny, don't try to role play as someone who is quick witted or funny.
[/quote]

Naw naw, this don't fly. People can't just RP themselves. That would be awful. It's like saying a writer can only write characters who are extensions of them. Like, holy shit, that would just all around suck.

It is true that, to RP traits that you don't have, you have to understand those traits. That does take empathy, which might make it difficult for younger people to pull it off, but that doesn't mean the effort isn't worth it. Hell, you might improve your own empathetic skills through learning how to write characters unlike yourself. 

But to add to everything else you guys said: yeh, you need to go deeper than dating-profile adjectives. Words like smart, funny, charismatic, etc, have limited abilities. You have to get a feel for who your character is as a person. What they like, what they don't like, how they see the world, how they see themselves. Everything else is extensions of that. 

So smart isn't enough. Are they mechanically inclined? Are they more book-smart, with the ability to remember terms and ideas? Are they good with numbers? People? Or do they have a knack for the tricks that make day-to-day life easier? Remember that most people are "Smart" with something, and that actual cognitive abilities play second fiddle to what you are smart at. Football requires a certain amount of tactical know-how and the ability to make snap decisions, but it isn't as intellectually respected as Chess which requires similar skills. 

Charismatic isn't enough. Are they good public speakers like a politician? Are they good at manipulating people on an individual level like Charles Manson? Or do they just naturally exude a strong presence, like a good Shakespearean actor?

Once you've worked out these details, you have to make them count.[i][u] Do not[/u][/i] write characters as avatars of whatever action you want to do. When it is time to address their reactions, plan them based on their personalities and then move on from there. It might make your plans difficult to achieve, but it makes the journey interesting and believable.