WBCS will be held with two stages.
Preliminary examination
Main Examination & Personality Test.

Here are some preparation tips you can follow for the exam preparation:

Get Familiar with the Exam Pattern : You should make a study plan for your study & know about the exam pattern. It will help you to make the preparation for the exam well.

Make Notes : Making notes is the essential part of any exam. If you make the notes every day during your study this will be really helpful at the last time of revision to take quick recaps.

Go through well with the previous year papers to know the level of the questions for the exam.

Good Luck!