That is a great question. As a teacher I would suggest that you remove any distractions that are preventing you from focusing while you are in class. Take notes and partipate in group discussion to get your focus on the subject at hand. If you are studying you need to find what works for you. Some people like listening to music, Some people like to draw or doodle. I teach a concept called mind mapping where you write or draw out your problem or subject and build off it .