Can you please suggest me a few referral books to study for GATE CSE 2019?
Being from a CS background, I'll give you the following algorithm.
Step1: Collect quality GATE material if you plan not to join a coaching Institute. Made easy has good materials and you can easily find them online.
Step2: Buy ample stationary as you would need. I thick copy for each subject is what I suggest.
Step3: Lay the foundation first i.e. make your plan of action. As in what time to study. How to study. I would suggest 4hrs a day only for gate is enough.
Step4: Complete the theory part thoroughly at first one chapter at a time. Mastering concepts is a must.
Step5: Solve previous year questions of the chapter you finished.
Step6: Repeat steps 4 and 5 for each chapter.
Step7: Once done with all chapters, sign up for mock test.
Step8: Do self-evaluation after every test.
Note: Revision and consistence is a must.
Also, keep at least one month for emergency reasons.
I hope that helps.