Hello,

When it comes to English section of CDS Exam, then the important parts are grammar, vocabulary and reading comprehension in the form of passages, you can refer wren and martin for grammar, norman lewis's word power made easy, you can read newspaper on a daily basis with special emphasis on editorial part, this will increase your reading speed, improve your vocabulary, understanding of the language when it comes to answering questions related to passages, this will also help you in general awareness section for covering the dynamic portion, for static portion you can read NCERTs book to build a strong base in subjects like science, geography, history, etc. Lucent'GK is also good book for static portion, there are various sites which provide monthly compilations of current affairs which you can refer, you should go through previous year paper in order to have an idea about the paper pattern, important topics, etc, also apply mock papers on regular basis to evaluate your preparation.