Hello Aspirant,

if you want to go for Master's degree in any if your preferred branches and further education , you can definitely give GATE exam. Its score is valuable to get a good position into a reputable PSU and other companies, since you have a Master's degree which exemplify that you have done more education and have a good practical knowledge. You should start early you will have enough time to prepare the schedule, check the syllabus and go through the reference books and materials which will help you further.Another advantage of starting the preparation early is that you will be able to allot much time to your studies and just focus on revision during the final few months so that you are at the top of your condition during the examination. If you don't want to go for online classes for GATE, you could study by self study mode since it gives you the strength to compile all your work with your own mindset. Gather all the study material available including youtube lectures, reference books, etc. But if you want to go for other materials like online classes and websites then BYJU's , , unacademy , GATE Academy and GATE forum are good. In order to track your performance, give online mock tests which will definitely help you with going and maintaining the pace.  Also, if you want to avoid online classes, then you should prepare your daily schedule and give time accordingly to every subject, get the whole syllabus at your fingertips and most important, take help and advice from all the available sources that you have

Hope that helps , good luck.