Help your child organize him/herself by purchasing a folder (for transporting homework back and forth to school) and a planner (for recording due dates).
Require that your child bring everything home every night. Assign a reward/consequence.
Homework and other assignments completed at home should reflect the child's true ability. One reason homework is assigned is so the teacher can see who does and does not understand the concepts. If someone other than the student does the work, the teacher thinks the student understands.
Students can always come back to school to get anything that they forgot to take home.
Both you and your child should check ProgressBook frequently to see if/when there are missing assignments.