Lets call study using your time to learn. Studying improves your performance. Doing well at school helps you get a job later or helps you get into that course you may want to do. You need to set yourself some short-term goals, and some long term goals to achieve your success in study.
Study is best in a quiet place away from family, noise and television.
It is best to have a permanent spot with desk, chair and a good light, a shelf and a storage place for your notes. Find out by experience when you concentrate best early morning, straight after school, or later in the evening. Study often-say four nights and one period in the weekend. Don't try to plan to do too many hours. Time spent is a lot less important than how much you get done.