No one has become an expert on the first day. You need a lot of practice to master any subject. Only Practice makes a man perfect. Online practice tests can help you in many ways.
NCERT books are written in simple but exhuastive way. They provide a strong foundation to every concept. They ensure a smooth and easy understanding of advanced concepts. NCERT books are refferred for major competitive exams like JEE and IAS.
Detailed solutions to the questions to all the chapters of the NCERT textbooks are provided to help students find best answers and compare with their answers.