Sorry for the length of the post!
For someone who had no clue about the GATE exam, GO came to the rescue! For those who are still oblivious to the power of this community, the websites https://gateoverflow.in and https://gatecse.in/ are such a huge support that you don't have to look anywhere else for most of your needs. So, a huge thanks to the creators and contributors of this forum. Furthermore, I implore the GATE 2018 toppers to add their own few cents if GO has benefited you, for remember the time when you read such posts and they motivated you.
I'd also like to add a few points as an advice for the times when the going gets tough for the aspirants :
1. When I started my preparation, I had already quit my job and traveled for two straight months. It was only after that, that I decided I wanted to study further and not get back to the industry. And so, I was extremely clear in my mind and all set for around next ten months of studying on my own. Obviously, you don't have to do any such thing because that just applies only to the travel freaks like me. But my point is, you have to "feel ready" to give yourself completely to the journey. And after that, it would really be a breezy, fun ride.
2. I had no clue about any subjects when I started preparing except Algo and DS, only because I was an active competitive programmer during college (although I had not remembered much by then). I started with easy subjects like Digital Logic and TOC, and then headed towards Discrete Maths, then Algo & DS and then towards the system subjects (DBMS, Compilers, OS and CN, in that order). I added Engineering Maths topics in between these subjects as breaks. (I love Maths!). So, basically, you have to plan the order of subjects and the duration of each. I took around 15 days for each.
3. I started with around 10 hours each day of studying in April, tired down to around 2 hours each day by the time I reached DBMS, and then again back to 10 hours per day during CN days. I study only when I am fully focussed. I don't study when I don't want to. What worked for me is that I love computer science - this beautiful world of logic where everything makes sense unlike the one we live in, especially in India where everything religious and cultural adds so much to the chaos. So, if you learn to love computers, think logically and analyze, you will make it.
4. Also, I love reading books. I read books for all the subjects and that's why my preparation took a lot more time than usual. I did not care about scoring in the exam only until the last two months. You can definitely score well if you learn from the videos and in fact, that's the right way to go when you don't have time. But I gained confidence in each subject only because I read all the books.
5. My parents are not much supportive. My relatives are weird. But who gives a damn. I quit a high paying job to pursue research and it's only people like us who can change the mindset of our society. So, if the society bothers you, you are not thinking straight.
6. How do you know if you are preparing your subjects right? Solve questions from the GO pdf (topic-wise questions) after each topic. It is a huge help. I have no idea how I'd have prepared if I did not have the book. Do not leave the TIFR and ISI questions. Gate exams are getting tougher. You need those questions.
Also, I attempted the aforementioned GO pdf around three times (skipping the easy topics the last two times). I did not attempt the previous year papers separately (except one or two to understand the distribution of marks and difficulty over the subjects).
7. I subscribed to three test series - MadeEasy, ACE and Testbook. I used to attempt Testbook topic wise tests once a subject was over. After my preparation was complete, I started revising all subjects and taking subject wise tests of MadeEasy. I took around all the full tests of MadeEasy and a few of ACE. Tests not only help you know where you stand in the crowd and which topics you need to work on more, but you can also use them as fun when the revision gets boring. At the least, take full tests of MadeEasy.
8. You need to plan. But more than that, you need to understand that plans never work out. You need to keep updating them. I planned to finish the syllabus by October and do revision and tests in the last four months. I ended up consuming two more months in finishing the syllabus. I took full tests only in January, but by then I had prepared my concepts well and was scoring under 20 rank in almost all the tests. So, you see, concepts need to be strong. You'll naturally score good in tests and the confidence will kick in.
9. Read all the blogs but your plan has to be your own. Analyze what works for you. GATE is easy because competition is not much unlike other exams.
10. Last but so not the least - Keep yourself hydrated. Never overwork yourself. Jog everyday. Breathe fresh air. Love computer science.
P.S. - I made silly mistakes of 10 marks - which was a constant during tests too. That made the difference between the topper's marks and mine. :(