The first thing you should do is to improve your strength, for example, you are exercising now. Secondly, you need a strong heart. Simply put, don't be timid. If someone dares to hit you, you stare at that person, and you stare at who is the most arrogant. You don't need to be good at fighting, but you need that ferocity. The school is full of idiots who imitate gangsters As long as you are tougher than them, they really have scruples and won't attack you again. After they start to have scruples about not doing it, if someone will do dirty things, such as throwing your books, doodling on your desk, throwing garbage and so on. As long as you find out who did it, take him down and beat him up!

Of course, if the gangsters in your school can use weapons and use them improperly, you should be careful. The above methods are not universal, but they can be used for reference. You can contact other bullied people, form an alliance, announce who has been bullied, and then all the allies will work together, so that those who do it will have a long memory.