A day before...

First, go through the gate syllabus and who is conducting the examination this year.

In my case, Gate 2020 is being organised by IIT Delhi.
The syllabus for CSE is this : http://gate.iitd.ac.in/Syllabus/CS.pdf (the link might not work later but the syllabus remains same throughout the year.)

First Part is planning :
1. Plan the number of hours you will study daily that will include working hours and number of hours on the holiday.
2. Plan the subjects to study accordingly.

Syllabus:
The order by which the subject should be prioritized are as follows (based on core subjects)
1. Algorithms
2. Programming and Data structures.
3. Computer Organisation and architecture.
4. Operating Systems.
5. Computer Networks
6. Theory Of Computation
7. Compiler Design
8. Databases
9. Digital Logic
10. Mathematics
11. Aptitude and reasoning.

Mathematics and Aptitude/reasoning.can be practiced easily in the free time too, while travelling or when bored or through YouTube videos. Will provide the better links once I find them.

So this was my schedule for a working day (Sleep - 6 hours):
5:00 am: Wake up
5:05 - 7:00 am Study
10:00 am: Reach Office (Travelling time is 1hr 30 min)
6:30 pm: Leave from Office (If no workload)
8:30 pm: Reach Home
8:30 pm - 9:00 pm - Get Fresh and short break
9:00 pm - 9:45 pm : Exercise
9:45 pm - 11:00 pm : Eat and some entertainment

So Its been really 2 hours a day on week days.