I would think that you need to follow a syllabus, a course of study towards an examination. Whatever level you are at now, you need to study for the next level. If you live in a country that has a system of examinations, then you should be able to get a syllabus guide for what students need to know in order to sit those exams. Once you have a syllabus, you can then search for books that will cover that. For physics, you will probably need applied mathematics. If you cannot do that at present, then you need to study maths at a level that will move you towards that area.