GATE

1. First go through GATE syllabus completely.
2. Discuss with your seniors or already qualified students how they prepared for the exam.
3. Get standard textbooks.
4. See the weightage of each subject (you will get it readymade), based on the weightage, give priority to subjects.
5. Go through last 10 years question papers to get to know the quality and difficulty level of the questions in each subject and start reading each subject/topics from a standard textbook.
6. After completing each topic, try to solve previous years questions from that topic.
7. Repeat instruction 6 for each and every topic of full syllabus.
8. After completing each subject try to solve previous mock tests (available on net), if you feel comfortable with that subject then keep it for final revision or else work hard till you have a command over it.
9. Repeat instruction 8 for all subjects and keep revising already completed subjects.
10. Finally, try to solve 8-10 full-length mock tests.
All the best.

It is good that you have taken the initiative early. That shows your enthusiasm. Now that you have decided to take the test you must reflect the thought "Why exactly do I want to write GATE?"
There are two perspectives to that question-
1. Decent score to get a good job
2. For further studies and if you are interested in research, it will be a good start.
Since you are in your second year, try joining an institute for guidance and attend the classes. Prefer going to the crowded ones for a better GATE score and low understanding if you want an immediate job.
(Or)
Go to a private tutorial who have less number of students and give more specific interest in feeding in the basics or the base of fundamental engineering. Here you will learn how things work instead of mugging up formulae.
Try searching for applications on your smart phone or laptop that keeps you updated about the exam. Believe me there are lot of such applications.
Although still in second year I wont recommend you to waste time in interesting yet not so important topics in your curriculum
Now these points that I mention will be of utmost importance.
1. Take down the syllabus of your specified course and stick to the syllabus.
2. Make sure you make one and only one notebook per subject, lets say its the fair notebook and you must keep it as a relic. Whatever you enter into this notebook should be very important points and no rough work or rubbish. Keep a rough note too to do those things.
3. Start watching videos from NPTEL. Its free and the best as far as I can go.
4. Once you start doing it enrol in a class and always attend it. Never miss a class.
5. Go slow take your time you have plenty of it.