What is wrong with my students?

Today I managed to mark the answer scripts from the previous mid-year exam for two form two classes I'm teaching. It puzzles me as to why most are not able to write decently. The frustating part is, during the weeks before the exam, I practically gave them the question that they are going to get for the exam, and even discussed with them on how to write the answers! Where did I go wrong?
I reminded my students every so often that they need to:

• refer to the dictionary
• refer to examples
• not copy their friends' answers blindly
• make sure that they understand what they are writing
• ask when they do not understand
• always do corrections for mistakes made

The list of advises and reminders goes on and on. And yet nothing seems to change. Am I fighting a losing battle here?

I find that many of my students are not committed with their studies. They do not put in much effort (or not at all) in whatever task given to them. They claim that they go to school to learn and yet...

• they do not bring their text books (the ones they got for FREE) to school
• their exercise books are always missing, especially when its time for them to hand them in
• they almost never do corrections
• many a time, exercies are done hurriedly by coppying from friends who copied from another friend whose answers are full of errors, but copied still since the teacher wants to collect the exercises
• some of the Muslims (especially boys) take 45mins (sometimes even 70 mins) to perform solat zohr or asr

How do I change these students mindset? Do I advise them? Have done that but doesn't seem to work. Negative reinforsement? Positive reinforsement? Have all been carried out but without success. So what next?