As you grade papers, have a stack of these printed and ready to go. One copy for them one copy to keep in their file to replace with the assignment when they hand it in. Good as a student reminder and to show parents that you offer lots of reminders and time to complete assignments.
On the day an assignment is due, the rule in my classroom is that EVERYONE turns SOMETHING in. If a student does not have his/her assignment, he/she must fill out one of these Missing Work Logs (which I affectionately call “The Yellow Sheet” because they are printed out bright yellow paper) and turn it in in place of said assignment. Blank logs are kept in a stack at the front of my classroom, and my students know to grab one if they are missing an assignment on a due date.