At the TESOL Convention 2013 in Dallas, Zoltan Dörnyei talked in a plenary about ways to motivate students.
He said teachers need to generate visions, because motivation is only present where there is a vision of your future self that involves knowing the language. The more intense the vision, the more powerful the motivation. As teachers we need to help students to SEE their desired language selves. They should be able to anchor their possible selves in reality and teachers should show them they are plausible.
You can do this by actively supporting their thinking, discussion, writing etc on subjects like:
where will you be using the language or skills in the future
This can also be done with tasks like:
Write a letter from your future self to you now – say thank you for the good decisions, encourage, scold if needed…