How competitive are you? Set yourself goals. Do you really want good grades, then unless you have a photographic memory or never forget a word the instructor says in class then you'll have to study. Write up question & answer cards and have a friend or family member quiz you. Imagine having the highest grade in at least one class. What would that feel like? Push yourself to at least get 80% or better on every quiz and test. Create in expensive low calorie rewards for yourself. See yourself graduating. Do you want to go to college? Doing well in high school gives you the golden ticket for entry and it will help you do well on your SAT score. With a college degree you'll have the opportunity to make substantially more income, have health insurance, retirement plans, etc. I don't think you want to end up 30 years old and working fast food for minimum wage. And you will be 30 one day, with or without a college degree. Buck up, education is a gift you give yourself. If you can't make it fun make sure you make it important. Marriage won't save you, 50% end in divorce. And welfare is a drag!!! Imagine yourself at 30; respect from peers and manager, nice home, car, clothes, hair cut, manicure or; rental or subsidized housing, using food stamps, dealing with welfare case workers, clothes from the second hand store, barely running car... You getting the picture. Studying now is you building your path brick by brick to the future YOU want to have. You're worth it!!!
If you want to get good grades and also make studying interesting, use what motivates you most close to you, create an excellent studying area and ensure you have adequate ventilation, good lighting and comfort. See more on http://www.wikihow.com/Have-Fun-While-Studying