Originally Posted by OmarHGondal

Please note that this thread is for the written part of the CSS exam only.
I have gotten several individual requests from aspirants seeking advice about different aspects of the written exam. Initially, I was thinking of making a Youtube channel where I could provide guidance. However, due to time commitments, for now, I have decided to share some guidelines for the benefit of larger body of students preparing and planning to sit the exam. Since I did not attend any academy and did not have any tutoring, this advice will specifically help those who are self-studying but will also be beneficial to those who attend academies.

General Advice
1) Remember the final goal. I have noted that many aspirants tend to lose view of the larger picture when preparing. It is quite understandable since the whole journey is quite time consuming and arduous. In every decision that you make, always remember that your goal is to score as high as possible in the written part as well as the interview. This is the only thing that matters--you are not sitting the exam to experiment with new subjects and explore new academic areas. You want to get allocated to a service of your choice and that requires a high score. The higher the score the greater the likelihood that you will get allocated to an occupational group that you put down as your first choice.
2) Do not ignore the syllabus. Do not just read what is in the notes that you got from your academy or what your teacher there told you. Study the syllabus yourself and make sure you cover all the topics.
3) Keep things manageable. In our attempts to score high we might set targets for ourselves that are far too ambitious. For instance, all of us have a tendency of gathering more books and material than we have the time to study thoroughly. What ends up happening is that we do not prepare well from any resource. Here is what I suggest: Initially, try to identify two/three sources (books, websites, notes etc) for each subject and start your preparation vis-à-vis the syllabus. If you feel the need to add more resources afterwards then do so. Otherwise do not.
4) Past papers are your loyal friends. Few of us leave enough time at the end to attempt and solve past papers. This is a big mistake. Starting 1st January, you should spend four weeks attempting past papers only. This will help you revise the material you have studied and will also help identify gaps in your preparation with adequate time to address them. Finding out a week before the first exam that most questions in the past papers seem alien is bound to cause panic.
5) Try and take it easy. While the exam is important and you should put in the hours, do not forget that you need to be healthy to perform well. This requires that you eat and sleep properly. Do not overdose on coffee or tea. You should also exercise everyday to keep your body in top form. The exam is taxing, physically and mentally. If you are exhausted even before the start or fall sick somewhere in the middle, a lot of effort and time might just go to waste.
6) Understand the Opportunity Cost of your time. Opportunity cost is an economic concept. In the present context it simply means that if you spend 10 hours preparing for your English Essay, you have 10 hours less to spend on other subjects. Invest your time in the subjects that yield higher marks with the caveat that you have the preparation to pass all the compulsories.
7) Make a schedule, manage your time, and hold yourself accountable.

The Compulsory Exams
Everyday Science and English Paper II: These are the two subjects in which you can score above 70%, if you put in the work that is required. There are several resources that have been provided for these two subjects already on the forum. Please consult those and remember the general guidelines above.
Pakistan Affairs and Islamiyat: These two may yield scores above 60%. I personally think Islamiyat should be renamed to Islamic affairs since it requires a critical analysis like some of the other compulsory subjects rather than mere regurgitation of facts. In contrast to some other people, I would advise that you do not waste too much time trying to prepare for Islamiyat MCQs. The time is better spent on improving performance on other subjects such as Everyday Science. See point 6 in General Advice regarding opportunity cost.
English Essay and Current Affairs: To the best of my knowledge these are the most unpredictable and least scoring subjects. I do not know what the latest trend is though. You should generally be aware of the current affairs since it has significant overlap with multiple other subjects and will prove beneficial in scoring high overall. English Essay should be prepared by attempting to write essays from past papers and then discussing with a group or posting online and receiving feedback.

The above is very brief guidance as I am a bit constrained for time. I will try and make a Youtube channel where I discuss the above in detail.

Optional Subjects – How to select?
My optional subjects were: Economics, Statistics, Psychology and American History. I could have chosen others but in line with point 1 from general advice above, I chose these because I knew these would maximise my score given my educational background.
In this section, I will give general guidelines as opposed to subject specific advice. If there is interest in advice related to these subjects and others, I can also give that upon request.
Let me make it simple. Optional should be selected based on three aspects, which I state below along with the respective weightages.

1) Your academic background (40-50%). If you are a mathematics student and you chose forestry there are two problems with it: 1) it will not look good for you in the interview; 2) you might get a difficult and tricky exam, which might fall outside of your knowledge. While there are exceptions who have done well outside of their fields, remember it is not the rule.
2) Scoring potential of the subject (30-40%): This may be assessed based on past trends and the nature of the subject. Though past trends may prove unreliable, we are not making our selection based completely on scoring trends. We have given a weightage of 40-50 % already to our academic background. As far as the nature of the subject is concerned, some fields yield higher scores than others. I scored 96% in my statistics exam and, no matter what, I could not have scored this high in other theoretical subjects.
3) Interest (10-20%). Some have this mistaken belief that subjects you choose should be those that interest you. Your goal is not to explore your interests via CSS. If you were applying for a PHD programme, your interest would matter. Not here. Also note that there is a high likelihood between subjects that interest you and your academic background as well as scoring potential. The point is to not select solely based on interest.

What if I fail?
You should not think about this. However, I know it can prove difficult to do so. If you fail, then you have two more attempts or one more attempt. Try again. If you do not have any more attempts, then remember it is not the end of the world. There are other careers that you can pursue and do very well. Always trust in Allah and remember that he has the best in store for you and that he is indeed the best of all planners.
I sincerely believe that the aim of our lives should be to excel at whatever we do. At present you are trying to clear the CSS and this is just a fraction of your life. Later, you might do other things and who knows what is in store. Be loyal to your ambitions, continue to strive and never lose hope. Failure is just a part of the journey.
Best of luck!
If you have any questions, do not hesitate to ask.