If you are wondering after reading the title, let me assure it is very much possible if you systematically do your preparation, you can crack CGL with six months of preparation, even if you are not an engineer.
Combined Graduate Level Exam is held by Staff Selection Commission every year (if there is no Court Case involved). It is a three-stage examination. Tier-I and Tier-II are online exams by MCQ tests, and Tier-III is an offline and written test. There is also Computer-based skill/type tests are also conducted for some of the posts.
If you are new with this examination, let me first tell you that in Tier-I there will be 100 MCQ for 200 marks, which you have to solve within an hour. Twenty-five questions each from Mental Ability, General Awareness, English, and Quantitative aptitude. Tier-II has 2 papers, one for Maths and one for English, for 200 Marks each. Two more tests are post-specific, which means everyone need not give these papers i.e. Statistics and General Studies (Finance and Economics).
Tier-III will be a descriptive paper that will be in English/Hindi. You have to write an essay, Precis, letter, and applications etc. The paper will be for 100 marks, and time given will be 60 mintues.
Now the main questions arise here, that from where should we start our preparation? My suggestion to all the aspirants is you should try to solve the latest CGL paper, which is available online by yourself of both the tiers, even if you do not know anything about CGL. This test will make you familiar with the pattern of the exam. You can assess yourself in a better manner that where you stand actually. I have seen many aspirants who have a set agenda in their minds that this will be the cut-off and I should be scoring this much marks. I am sharing my experience of mentoring CGL aspirants for the last seven years that this strategy will not help you; always try to score maximum and give your 100% in the exam. Never hold yourself back while preparing for the exam.
After giving the latest question paper, you should start your preparation, and you should try to develop a habit of reading newspapers (either Indian Express or The Hindu) daily and try to note down the words you don’t know before. Reading newspaper daily will benefit you in 2 ways, it will improve your English grammar and vocabulary, and it will cover a significant portion of your current affairs. By reading newspaper you will be confident to read the lengthy comprehensions in the Tier-II exam of English comfortably.
Regarding booklists and question papers, I will suggest you to go for two standard books for clearing your concepts English Grammar and Comprehension by S.C. Gupta (selective reading as per your syllabus) and Quicker Maths by M. Tyra (selective reading as per your syllabus) and buy any standard test series which have topic wise PYQs and any test series for mock tests.
There are majorly 26 topics in Quantitative Aptitude, which you have to prepare for both Tier-I and Tier-II. Make a list of topics and paste it where you can see them daily. Start your preparation with algebra and believe me; it will help you in a big way. It is one topic which will help you in solving questions from almost all topics. Whenever you answer the questions, try not to use pen/pencil, and do the calculation in your mind without writing, it will feel absurd initially and a bit time consuming but within one month you will be used to this, and it will save you a chunk of time in the real examination. Allot every topic 5 days for quantitative aptitude and solve at least 50 questions each day from the topic. It will take around 5 months to complete Quantitative Aptitude both for prelims and mains. Use the last one month for practicing the mock test, 2 tests daily.
For English, you can divide the syllabus in 3 broad categories (i) Grammar, (ii) Vocabulary (iii) Comprehension. The set of rules for the grammatical portion can be found in any standard book. Read at least ten rules every day and solve 50 questions daily on the rules you have studied. Solve a comprehension daily (on weekends try to solve Para jumbles) and learn 10 new words daily (including one-word substitution and Idiom & Phrases). It will cover all the syllabus of English both for Tier-I and Tier-II. Give at least 50 Mock tests before appearing in the exam.
For General Awareness, put your focus on current affairs and science, you will get good marks in GA, read compete lucent once and you will be good to go to the exam. For mental ability, I will not suggest you any strategy but the advice is to solve at least 50 mock tests before appearing in the main exam.
For Tier-III, you should be aware of all the formats of letters and applications, reading newspaper will undoubtedly help you write essays and do Precis writing. Do 15 days practice before the actual exam, you will score good marks in that exam if you follow my earlier strategy.
I hope this strategy will help you to clear this exam in your first attempt. Feel free to ask your queries in the comment section below I will personally answer all your exam-related queries. Best of luck for your exams.