hi irfan , 

yes , it is possible to crack  gate with out coaching . but you will have to study and practice and write mock exams in plenty number for cracking gate . 

• Select your subjects of focus according to their maximum weightage in the GATE exam.
• Make a schedule for study and strictly follow it.
• Make notes of the important formulae so that you can revise during the last week of your preparation before the exam.
• Solve 15 years question papers in descending order i.e. start from 2017 then 2016 then 2015 and so on.
• Practice numerical questions as much as you can.
• Try to give online mock tests as many as possible.
• Make a habit of revising the topic at the end of the day which you had studied that day.
• A sincere group study could help you attain better understanding of the topics or concepts which you failed to on your own.Do not refer more than two sources for a subject, as it may confuse you.
• Analyze syllabus properly. Don’t study beyond it.
• Don’t spend much time in theories; instead spend time evaluating and understanding the fundamental concepts.
• No need to cover all the subjects because some subjects covers hardly 1-2 marks, just go through the previous year’s questions for those subjects.
• Don’t study new topics few days or even a week before the exam.
• Don’t panic before GATE exam, as it may reduce your confidence level.

all the best