Your job at this point is to take everything you know and, as the CMO for capital one, improve every aspect of the mailing that you can in an effort to get the target audience (me in this case) to take the action that you desire (sign up for a card I think)
Ok?
You can present your recos graphically or, if your artistic skills are like mine (NOT good!!) in writing
If the latter I strongly suggest you use bullet points to keep your ideas focused and simple
Ok?