What i found in my last 4 year that most of the aspirants are started preparing for SOM,RCC,SA subjects and they not provide concentration on maths and aptitude. As on date Math + Aptitude bring the 30 Marks for GATE exam.
So from my analysis we all need to focus on following subjects :
1. Geotechnical Engineering (Soil Mechanics)
2. Environment Engineering
4. Water west engineering
5. Fluid mechanics
Following video will provide you more clarity for GATE 2020 planning. Hope you Enjoy.