Right now focus majorly on core subjects of GaTe EE and fron second to third year end you should have completed syllabus. By third year end and fourth year start you must have appeared for 25mocks atleast and then analysis of mistakes and weak zone sis mandatory and keep revision. 

Preparatory tips sharwd below. 

https://engineering.careers360.com/articles/how-prepare-for-gate-without-coaching/amp