My 1st graders seem like they may have been ready to come back to school...
"In 2015, I will stop yelling at my mom."
"In 2015, I will stop running through the laundry when my babysitter is trying to fold it."
"In 2015, I will not hit my sister when she makes me angry."
My 2nd graders ended up sounding very mature...
"In 2015, I will watch less t.v. I will go outside or play with my legos instead."
"In 2015, I will spend more time with my family. We can play board games or go to the park"
"In 2015, I will help my little sister more. I will teach her the ABCs and to use her manners."
I recommend reading the book Squirrel's New Year's Resolution before writing to explain the concept in a primary-friendly way.