How do I study? Well, the best foundation for good grades is to schedule normal study time five or six days a week, and to use that time for school regardless of whether you have a specific assignment due or not. For high school a very good rule of thumb should be to schedule a minimum of two hours a day, five days a week, and then add some time on the weekend when you've got unique reports or need to read a novel. Schools and teachers vary in how much outside work they expect. Music and some other disciplines will also need daily practice.
For university, the rule of thumb is always to schedule two hours of outside research for each hour you have in a classroom. For instance, say on Mondays & Wednesdays you might have a math class from 10 to 11:30, and an Art class from 1-2:50, and on Tuesdays and Thursdays you've English from 9-10:30, History from 11-12:30, and Psychology from 2-3:30. You are taking about 18 credit hours and are spending about 18 hours each week in class, so this means you should spend about 36 additional hours a week in study and class preparation.
For example, you might arrange your study time like this: Mondays and Wednesdays go to class at 10. After class go to the library to do math homework, then go to lunch, then to your afternoon class. Then go home or to the library and work some more, switching subjects or location whenever you find your concentration waning, but try to keep working on something. study groups are an excellent way of keeping your concentration and getting help for hard subjects.
If you organize a block of time starting with your first class of the day, you will be able to quit later in the day and have fun without guilt or worry. So Mondays and Wednesdays you might start at 10 and end at 9, and Tues & Thursdays you start at 9 and end at 10, and on Fridays and Saturdays you start at 10 and end at 4. This routine allows you an hour for lunch and short breaks. These tips on how do I study might not be applicable to all. Some people need more breaks than others; other people study best before sleep. You can work it out to suit what's very best for you, but make sure you put in two hours for each and every class time hour each week. Pacing yourself is the greatest way to avoid panic as assignments come due, and is also the greatest way to get excellent grades.