During my brainstorming, the following themes came through: technique, ear/rhythm/sight-reading, and practice frequency. To be honest, those are the key themes every year, but these are areas I really want my students to shine in this year. So, I had to tweak the student challenges and incentives a bit.
This year, I modified my incentive program slightly to incorporate "musician survival skills". These are the areas that we as teachers and performing musicians know are necessary: aural skills, sight-reading, chording, transposition, improvising, technical skills, and practice frequency. They are also the areas that most students either gloss over or ignore.