English Precis & Composition Paper:
1- First learn grammar from scratch. You can use any book. Wren and Martin is a good option. You can learn at home without any help. If you feel any difficulty, you can consult any good English teacher who teaches at Masters level. Keep practicing exercises.
2- Start memorizing word lists for both synonyms and antonyms. There is absolutely no need to learn extensive lists like GRE master list of 3500 words. 1000-1300 word should be sufficient. I memorized two lists:
i) Manhattan 501 word list
ii) GRE high frequency list
Words of both lists are not above 1000 if we compile them together. They should be sufficient.
Usually synonyms and antonyms are not repeated in papers. You can solve past paper objectives to see patterns which can help you. They put eye catching options. Sometimes there are three similar options and one different. Usually the odd one is the answer etc. It does help in choosing when you absolutely have no idea about the word being asked.
3- Lists of idioms and pair words. I did them from Hafiz KarimDad Chughatai's book published by Caravan. Give tests at weekly and monthly basis. Keep revising after you are done. Do past papers of this portion. They do repeat it.
4- Do learn change of voice and narration. Practice dialogue narration as it is being asked.
5- For above all steps any good Masters level teacher can help you. When you are done with these, time for most difficult and technical portions come.
At this point, you should go to professional CSS English teacher. They will teach you techniques of all subjective questions. Get them to check your practice at regular basis. First, learn the basics of each subjective question. After that, start practicing past papers of these subjective portions i.e Precis, Comprehension and Translation. Get is checked from professional.
1- Translation: They expect you to write in idiomatic expression. If you know the right one, do write it. If you do not, go for literal translation. Use as many idioms as you can fit according to urdu paragraph. It does help in scoring more. Do not write wrong if you do not know any. Just do the literal translation. Write neatly. Do not erase or cut otherwise, you will lose marks.
2- Comprehension: They ask from the paragraph. Sometimes they ask your opinion or what you have understood from the passage. Occasionally, they give few underlined words and you will have to write either meaning or explaining sentence. Never write copy pasted answer from the passage. Write in your own words. Each question carries 4-5 marks normally. Write accordingly. You can write a part of the question to increase length of your answers. Half page is a decent length for these type of questions. It can be more or less according to question. If it straightly asks yes or no, do not you ever write only yes or no, explain why you wrote yes or no.
3- Precis: Make only one title. Do not make multiple. Try to write a phrase in title and not a complete sentence. Length should be between 3-7 words. It should be well thought and self explanatory one. It should be the main theme of the entire passage. Give 10-15 minutes for selecting a title. Give heading "title of precis" at start with marker. After that, start precis. Give heading of precis. For precis, read the paragraph at least thrice. Make two rough drafts at the end of the paper. In first draft, write the extract of paragraph. In second, write all important ideas and omit unnecessary and repeated ideas. Adjust the word count here roughly in the same draft. When you are done with that, write final draft neatly in section where you started solving precis. At the end, give two heading. First, world count of original passage. Give sign of = and write counted words for example (=350 words). If you have time, count each and every word. If you do not have, just count words of one sentence and multiply by number of rows. Sometimes they give word count in question. Check if it is the case. Second, heading of word count of precis. Try to count all words and write it. They should be 1/3 of original passage. +/-5-7 words is allowed but the closer you are the better is your precis. If count is less, you might have omitted some important concept. If count is more, you might have repeated the same idea. If words are 350, word count should be 117+/-5-7.

Try to solve entire objective portion including MCQs and objective questions of subjective paper such as idioms in first 1 hours. After that you should solve either translation or comprehension. Comprehension usually takes 30 minutes. Translation paragraph can take about 20-30 minutes. 1 good hour is required for best precis. 15 marks for title and 45 marks for precis. Do this question at the last. Try to solve paper 10-20 minutes early. Use your presentation skills to give good looks to your paper. Read you entire paper at least twice and correct mistakes if there are any. Do not create mess by cutting too much. Just draw a line on word and write above it. It is better not to make any mistakes. If mistakes have been made, make sure you correct them.

Here, some people will ask me why I am suggesting to go to Masters level teacher for grammar. The answer is that professional CSS teachers do not give you that much time. If you will go blank, I am afraid they will keep on correcting your mistakes in basic English. You will not be able to learn anything productive about CSS English paper. You should be going to them to learn techniques, tips, tricks and paper attempting strategies. Also, your aim should be to get your practice evaluated and not to get your English corrected.

My expression is different but I do not write perfect English. I do a lot of mistakes too including grammatical and spelling mistakes. I did invested a lot of months in improving these things. I read a lot of books and novels in British English. Watched a lot of movies and TV series with subtitles. It improved my English. Still there are a lot of mistakes which I do. They are generally so minor that examiners usually ignore them. Your English should be at least of that level. I went to learn and practice only when I was ready. You should do the same. Otherwise, you will only waste your time, money and chances.

My Marks in CSS and PMS:
CSS 2019- 49
CSS 2018- 56
CSS 2017- 49
PMS 2019- 62
PMS 2017- 55