Look at examples of winning Chairman's entries, which you can easily find online.
MOE's winning entry from 2007 is here:
http://www.moe365.org/gfx07/chairmans/awardentry.pdf
We also gave a presentation in 2008 on how to prepare your entry. It is dated but the basic concepts are the same:
http://moe365.org/moeu/chairmans_awa...ation_2008.ppt
It's always a good process for a team to do, even for a second year team. You can just build on it each year.