Motivation

Motivation is a very important  aspect to teaching.

Different Schools
If you're at an academic school, there's a change your class is already pretty motivated, and maybe you won't need to provide motivation. If on the other hand you're at school with low motivation, there are some things you can do to help motivate the students.

Background
Firstly, people respond to incentives. If you ask the class, "Who knows the answer to this question", there's a good chance that a low-motivation class will just ignore you. So the trick is you have to give them a reason to participate. For example, make everyone stand, and then ask the same question. Let them know that if they answer they can sit down. That way, students prefer sitting to standing, and so they are motivated to participate. This is just an illustration of the point. If you did this every question, the class will grow to hate you... But as a principle it is very useful.

Incentives
See the article on Incentives for more details on how you can encourage your students to participate.