Hi Ana,
By trying the various motivation techniques you are setting the stage for the students to move to the next stage in their professional development. As you well know motivation is a constant effort. The issues of daily life, being a student, and making a living all contribute to weighing the student down to the point that they often cannot see that they are making progress toward their ultimate goal.
A key point in relation to motivation is that it needs to include both motivation directed toward the student as a person as well as the student as a student. This means that by giving friendly support at a time a student is really down, tired or discouraged helps him/her personally. Encouragement and support given in direct relationship to course content helps with motivation towards the career goal. Both have to be given at the appropriate times.
Good luck with your efforts.
Gary