For the first month of school, instead of assigning jobs, have each student get his or her own day to do it all - line leader, run errands, etc. That way each child can feel special and you avoid having students fight over who gets to do what.
To help students learn about each other at the beginning of the year, one teacher has students do "Hanging Autobiographies." Students make a poster of their life. They bring things from home such as baby shoes, pictures, etc.
On the last few days of school, have your students write letters to the next year's group telling them what to anticipate. Then, on the first day of the next year, the new students read the letters as they discuss their own expectations and goals.