PGCET Karnataka is a relatively easy exam compared to Gate or other entrance exams by Private Universities like Manipal Entrance Test. But don't take it lightly. Old question papers are much significant here than in any other test. Might be MBA or MArch, ME or MTech the funda remains the same. Dig through old q papers, find the way of asking questions, get your own Fundamentals of the Topic notes, devote some time for solving 1mark interview questions and there you go. You will find yourself in top shelves of PGCET rankings.

PGCET has a different approach than most of the other competitive examinations. It seems easy in the beginning but has its own tedious things which become tiresome over time. So without taking it lightly just focus as I have said in my answer. Devote 5–6 hours a day for study and 3hrs at least to solve different interview questions which you will find in sites like Indiabix and you will thank me after the results. :)

Hope this helps. And All the very best.