One simple idea that came to me to help students motivate for the whole year. Tell students they start the year with an A. Structure the class so that all students will be able to send home an A in math for the first progress report. Then communicate the expectation that things will get harder and students are capable of keeping that A grade. Parents and peers might put a bit of pressure that could help motivate students to work hard to preserve that grade.

I would like some feedback and possible drawbacks on this idea?

One model for the hierarchy of reflective practices for teachers.

Level One: Teaching Techniques and their Effects
Level Two: Justifying Educational Practices and Goals
Level Three: Relating School Practices to Larger Social Issues

Source: Van Manen, "Linking Ways of Knowing with Ways of Being Practical." Curriculum Inquiry, v.6. 1997, pp. 205-228.

Have students work on various assignments in content specific tasks. Have the student share what they have learned with the class or a subset of the class. By having a group of students that are experts in at least one area each, gives you people to call on for specific ideas. 

Any strategy to create authorities in the classroom for different concepts gives students the chance to claim understanding and yields an opportunity for expertise which builds the possibility for future mastery.

Some ideas for techniques to integrate formative assessment into your classroom:

1. Quick Writes: Give students two or three minutes to write about what they heard or learned in class.
2. 3-2-1: Jot down three ideas, two examples of uses of the idea, and one unresolved question.
3. Muddiest Point: Student disclose the least clear or "muddiest point" in the lesson.
4. Quick Check: Use whiteboards or index cards to have ALL students write down answers. Have students hold up answers all at once to gauge understanding.
5. Idea Wave: Have students list three to five ideas, then go down the line like a "wave" at sporting games and collect ideas until you have enough to work with.
6. Tickets: Ask a specific question about the lesson. Have students respond and give the response before they leave class or before they enter class the next time.

Source: AFT's Educational Issues Department: American Educator, Vol. 37, No. 3.