Set goals for yourself. Having goals to work towards can help you stay motivated and focused. This could include anything from getting good grades to making the varsity team.
Break down your work into smaller tasks. Large tasks can seem overwhelming, which can make it difficult to get started. Break down your work into smaller tasks that are more manageable.
Take breaks. Don't try to study for hours on end without taking a break. Get up and move around every 20-30 minutes. This will help you stay refreshed and focused.