collaborative character building focusing on the combined carrot/stick of aspects, followed by a prolonged, possibly painful, learning period during which you 'encourage' what you consider to be 'good roleplaying' with compels against those aspects and other, temporary, aspects gained during play (or against aspects they interact with in the form of those universe-sustaining objects)
That, and mature discussions with the players involved on what you consider 'good roleplaying' to be, and why you think it's beneficial to the enjoyment of the group as a whole.