While grammar books focus on structure, most students need a comprehensive course that covers Reading, Writing, Listening, and Speaking. Cambridge publishes several major series that are used in classrooms worldwide but are also excellent for home study.
Look for icons in the book labeled "Corpus" or "Common mistakes." These highlight errors that real students from your language background (e.g., Spanish, Chinese, Arabic) make most often. Memorizing these saves you from losing points on exams. cambridge english book