Teaching middle school is certainly challenging. It's difficult to motivate those students that just aren't motivated by their own grades.
Our school year is divided into six 6 weeks periods. At the end of those periods, I hold a classroom raffle to raffle off bags of chips, candy, Free HW Passes and Drop the Lowest Daily Grade passes. The kids turn them in to me whenever they need a free pass.
I issue my students "raffle tickets" throughout the 6 weeks when they turn in HW on time, get an A on a test, or if they make a true effort to participate in discussion. I collect all of these tickets daily and then at the end of the 6 weeks, I draw 10 tickets per class period.
Here is an editable word document with the templates for these passes. HUGE MOTIVATORS!