Motivation

There are different types of motivation. But intrinsic motivation is most important to encourage.
This type of motivation is when students are interested in learning with out the aid of a bribe.
"If you do well, we'll have free time" is better than"I know you can do well, try and beat your last score!!" In addition to encouragement call out the students who got 100 and hand them their paper with an applause from the class.
If you give a bribe your class they won't cooperate with out one.

Another Tip to Increase motivation is to post student work on the walls or hang them from the ceiling (it may be the only space left). This is to instill class room pride. They get to see their work displayed and the work of others.

Give the students a choice. They will always work harder on an assignment they choose to do.

Knowledge of factors and situations that promote or diminish intrinsic motivation.

Have a token economy. It allows the students a way to earn treats and promotes a positive work ethic.

Try to use interactive and student centered learning. The time were actual learning takes place is the time were the students are active. One way to do this is to have lessons and reviews structured as games.

Use praise and rewards. The key to good behavior is to promote positive actions not just to punish negative actions.