How can a student improve his grades?

Study hard, and focus as much as possible! Take small breaks and study and do your homework  in quiet areas  where you will not be distracted. Turn off your phone, and any other distracting technology. If that does not help, maybe consult your parents about getting a tutor or going to afterschool classes. Maybe even consult your teacher  about doing extra work, or ask the teacher some questions!

Your grade goes up when you score higher on assignments and tests, so in order to improve your grade, you must improve your individual scores. To do so, a student should set aside time to study and memorize the material. If there's something they don't understand, they need to take proper measures - such as talking to a teacher or librarian - to be sure they do in the future. In order for this to happen, a student must preform well, which requires a nourished body and mind. Getting enough sleep, food, and water are very important as well. Coming to class on time, well-rested, and fed helps aid the learning process as well as overall grades.