Instead of choosing a random topic from the syllabus, you must break your preparation into sections. Sub-topics from each section should be selected and then strategy on clearing concepts must be made. Never leave any concepts doubtful or unsolved. Once done with the syllabus and concept clarity, you should move towards solving PGI Previous year's papers. Give PGI mock tests as many as possible. Time management is one more important thing you should look upon. Remember that practise will increase your efficiency.

Go through this-

https://medicine.careers360.com/articles/pgimer-exam-pattern