Hello aspirant,

I will give you a month-wise strategy to prepare for any GATE Exam-

For June, July, August, September, October and November -

1. Make sure that you know that you are going to prepare for GATE and not collect enormous knowledge. This is important because you clearly need to distinguish the necessary from the extras.
2. Deactivate your Facebook account if you have one. You can live without it.
3. Get a correspondence course from some coaching. There are two coaching institutes in which offer good correspondence courses for Chemical Engineering - Engineer’s Institute of India (EII) and GATE Coach. I would strongly recommend EII. (Mentioning this because I am a Chemical Engineering student)
4. Carefully select the books you will be following to start your preparation. I will give a list of the books at the end of this answer.
5. When the coaching correspondence material arrives, carefully notice the topics that are ACTUALLY in syllabus. Those books contain a plethora of knowledge which you do not need to crack GATE. You need to sort out things that are necessary in syllabus.
6. Start making your own notes from books by keeping a check on syllabus from coaching correspondence.
7. At the end of every subject, take the book containing GATE previous year subject wise questions and solve it thoroughly.
8. At every fifth week after finishing a subject, solve the previous year questions again to keep a check on concepts you wrote.
9. Buy a test series around the month of October and start taking subject-wise tests. Two tests per subject is sufficient. Taking more tests would be a waste of your time.

THIS SHOULD BE DONE BY THE 30th NOVEMBER.

Now I will tell what to do in month of December and January.

December -

1. Take all the notes you have prepared and revise them between 1st to 15th December.
2. From 15th to 24th December, solve all the previous year GATE question papers again. This should be 4th time that you should be solving GATE previous year papers.
3. From 25th December to 31st December, clear out all your doubts that you have ever accumulated.

January -

1. Take your first full length Computer based test on 1st January. On this day, you will know your strength and weaknesses. From this test, you will analyze the minute concepts you need to work on for next 30 days.
2. After the full length test is over, spend 1 hour more to analyze the questions you got incorrect. THIS IS THE MOST IMPORTANT STEP TO SCORE A TOP 100 RANK.
3. After your first full length test, revise all your subjects again between 1st January to 5th January.
4. Take your second full length test on 5th January. You should see improvement. And if you do not see improvement, then don't be disheartened. Start revising all subjects again.
5. Between 8th to 12th January, prepare your formulae notebook. From this point on, you will be revising your formula notebook three times a week and constantly be working on the gaps you have to fill in your preparation.
6. Take your third full length test on 13th of January. This time, there will be immense improvement. You will feel confident and happy.
7. On 15th of January take any one full length GATE paper from 2011–2019. Set the timer of 2 hours instead of 3 hours. This will help you build up your speed.
8. Revise your entire syllabus again between 15th January to 19th January.
9. On 20th January, take two previous year GATE papers with a timer of 2 hours. Take one paper in the morning shift and second paper in evening shift.
10. Starting from 20th January, you will be solving only GATE previous year papers and Full Length tests from test series till there is one week left for your exam.

Last week before Exam -

1. DO NOT take any tests.
2. Keep on revising your formula notebook everyday. EVERYDAY. ALL. THE. SUBJECTS.
3. Sleep for 8 to 10 hours per day.
4. Do not eat anything which you do not eat daily.
5. Do not learn anything new. Keep on revising what you already know.

On the day of Exam -

1. Chill out and take the exam. A rank under 100 awaits you for sure.

Good Luck.