How to Get 90% Above in ICSE Boards?

Well.. I have not studied anything in my Summer Vacations ( 52 days ). But now I want to study.. and even want 90% above in my Boards (March 2012)..Please tell me what to do also what should be study schedule? Main Emphasis on Physics(15 or 14 chapters);Chemistry(12) boilogy(22) History (20) Geography(15) ...please help me!!!!! 5 ***** Guaranteed!!!!