I guess the main thing you need help with is how to manage your time since you are working and are also looking to crack GATE. You'll have to make sue of your office hours and the time you have at home. Begin with going through the syllabus and the previous year papers here on the website https://edurev.in/courses/7824_Electrical-Engineering-EE-For-GATE-2019 and make a study plan with goals on when you are going to finish each subject. Take tests- lots of them- and improve upon your mistakes. This is what will make a difference in the quality of your prep and make sure you are preparing right. Be consistent and make sure to devote a certain number of hours everyday.Also, most importantly, never doubt your preparation simply because you are working and preparing at the same time and it 'seems' difficult. It'll take a bit of time, but I am sure it's do-able. All the best!