Winter:
You have to harden yourself in order to get through. You cannot take on responsibility for your students' lack of desire to study and do well. Trying to do so will lead you through sadness, desperation, frustration and to burn out.
I have taught at US universities for over 10 years, Spanish at various levels, both to students who wanted to be there and those multitudes who did not. Tough for them. Their crappy attitude and disinterest in learning anything at all and using their brains to become a more informed individual and future citizen has nothing to do with me.
Your job is to make sure you are in class, completely prepared to teach, with full knowledge of the material. You can motivate, cajole, and be passionate about your subject. Passion and enthusiasm often touch a student more than threats and quizzes. But you can also offer many quizzes and pop tests and you must give them regular, timely feedback on their performance so that there are no nasty surprises when it comes time for a big test or exam.
The hardest thing for me to accept when I began teaching in the US after being educated in the UK was that as a teacher I always had to make sure I could defend myself. I always make sure to keep scrupulous notes on all exams, quizzes and essays assigned, on all grades earned, and additional notes on particular behaviours: lateness to class, absence, failure to hand in work, and "mental absence" in class. I am always prepared to be confronted by a student and inform them of exactly why they should not be surprised that they failed my exam/essay/course.
Maybe it is particular to language classes, but the final grade is always made up of multiple sections: give a grade for participation and attendance, for quizzes, for exams and essays. You can be more flexible with participation grades, but not with the rest. You can also bump up the participation grade to a larger percentage of the total final grade. That way, if they know that 30% of their final grade depends upon their participation, they may be more inclined to:
--attend class
--come prepared with texts read and notes taken, questions to ask
--participate in class discussion
I cannot stress this enough because if your students do not come prepared to class, I don't know how you can teach it. At least, this is true for language classes. Nothing will happen in my Spanish class if my students have not done their homework because, quite simply, there will be nothing to discuss and no-one to offer opinions except me.
I refuse to give students the answers, spoon-feed or hand-hold. That is not teaching, it is capitulation, or mothering. You cannot adopt a maternal role with respect to your students or they will milk it for all they are worth. If they don't do the work, they don't get the grade. It's that easy.
I have always maintained, and so have the good instructors I have learned from, that every student has the right to fail. Old Chinese Proverb: "The teacher can open the door: the student must walk through it alone." As the other poster said, sometimes failing a course is the massive wake up call a student needs to realize that after they leave college they will be out in the big, bad world where failure to do the project assigned does not lead to being given a second chance to complete it: it leads to being fired.
Hope this helps,
Clare