My mother had a big problem with my middle brother when he was 11 or 12. He was satisfied with just getting by and almost failed the entire year because he didn't want to do his homework. He could do the work, he just didn't care. Mom had to sat down with him and explained on a nightly basis her feelings about school. He often sat and acted like he wasn't listening but she still talked to him every night. She told him that it was important for him to do his best. He was a very smart you man and she knew he could do much better than he was doing. She then told him until he could show that he was responsible for himself that she would do everything in her power to make sure he did what he was supposed to do and succeed in school. She explained that though he didn't understand the importance of an education at that time, she did and it was her responsibility as a mother to force him if necessary to succeed. So this is what she did for the next semester.
1.) She contacted his teachers and explained that she would be contacting them almost daily if necessary about his progress. She was instituting some techniques to force him to perform better. She asked if there were any problem areas in particular that they thought she should help him with. She also explained that he would be carrying a notebook to write homework assignments in and that she was asking all his teachers to sign it during class everyday...even if there was no assignment and communicate anything they felt they needed to in that notebook. And in return she would check his assignments every night and sign off as well.
2.) She explained that all his tv privelages and playtime outside was suspended until the end of the first progress report. He would not be allowed any tv, video games, or playtime outside during the week until the first quarter was over and she saw from the progress reports that he had improved. And my mother didn't make idle threats.
3.) She got his notebook and told him that it was his responsibility to write his assignments everyday and remind the teacher to sign off. If he forgot, he would lose additional privelages for that day. Example...he would have to go to bed 15 minutes early that night. He would not get any dessert after dinner. Or if it was persistent, he would not be allowed outside one day on the weekend.
4.) She would call the teacher if he forgot to have his assignment book signed.
5.) Once or more during the week she would walk him into the school that morning to talk to one or more of his teachers about his progress or after school. (he was thoroughly embarrassed) Mom explained that since he was not taking his part of his education seriously and acting like a small child then she would treat him like a small child.
6.) If he wrote his assignments everyday for the whole week and got no bad comments in the book from his teachers then she would reward him with something special on Friday night or Saturday. She might let him go out and play Friday after school, let a friend spend the night, let him play his video games of an hour or something like that.
Mom got across to him that semester that his education was very important to her and though he might not understand how important it was...he wasn't allowed to be a slacker. Something sunk in because he never pulled that again.
Her last and greatest idea for encouraging her children was to get us all really hard, really crappy jobs when we got old enough to work. We were only allowed to work in the summer and she found us the nastiest jobs she could find. We worked in a packing warehouse in 100 degree heat from sunup until sundown for minimum wage ($3.13 an hour then) two summers. My uncle got both brothers hired on at his job in a factory two summers in a row working like dogs for minimum wage. The first two years of college my brother worked in a dog kennel as the official "pooper scooper".
She then had a rule...after you graduated if you didn't want to go to college that was your choice but you would either move out or have to start paying rent, paying for your own insurance, and you still had to follow all her rules including midnight curfew.
If you gave her one year of college, then you could stay rent free and she would continue to pay your car insurance.
All three of us went to college and graduated with honors. It really made a difference to us that our parents really cared and just didn't talk the talk. We knew that they meant what they said because they would go to any effort to prove they weren't just full of hot air. They were willing to sacrafice their time to encourage us and we knew they really cared.
Hope some of that helps.