Apart from this as you had asked for some effective Materials and Topics which can made your GATE performance better and easier, I had followings for you:-
List of Best Study Materials for GATE (Civil) 2011 (Attached pdf below)
Vedio Lectures, of IIT Classes for Civil Engg. From Youtube
Lecture series on Mathematics-1 by Prof S.K.Ray, Department of Mathematics and Statistics IIT Kanpur