Making a DepC in IIT KGP is the easiest they say among all the IIT's . I did not feel so . Making a Department Change requires an extraordinary combination of LUCK And HARDWORK
LUCK: According to one of the rules of Department change . The net change of the strength of a department must not be more than 10% hence your LUCK comes into picture here . Suppose you score 9.4 and in your department 3 people can only make a DepC . If the top three of your department are all above 9.3 then NO DepC
HARDWORK: hardwork is obviously required in order to score good and clear the cutoffs of the particular branch enabling you to make a DepC.
Finally I would say , even if one wants to make a DepC to CSE ,you need not just sit in your room and keep on mugging , Enjoy the Campus Culture , Take part in Various Events and Study when you need to study .
IMP:Attending all the classes will surely give you a better CGPA than not attending and studying on your own !