Sorry, but it sounds like you´re faced with a task like this for the first time and you don´t know what you need or want. If the ad is intended for print magazines, you have to work with (at least) 300 dpi high quality images. And you need to know the guidelines of Nissan´s branding (fonts, color schemes, ideas, target audience) to come up with useable concept.
Hi, I would like to take the time to thank every participant in this contest. Many great designs have been submitted through this thread and via PM. The winner will be announced within the next 24-36 hours. The designs submitted were very competitive. Thank you I have been in this field for over 5 years, I'd suggest you keep your comments for yourself.
More importantly where's the contest holder Seems like he made time to answer on other threads for templates he is trying to sell but not on this one where he is supposed to pick a winner or at least provide some updates. BTW sorenson, that's a really cool design.