First of all, don’t start from scratch !
Identify the companies that are coming for placement drive, open google and search for placement experiences of the companies, identify the topics for Quants, overall question pattern and overall selection process pattern for it and prepare accordingly.
After clearing two companies (Wipro and IGATE) written round, I can say that :
Be well prepared for verbal and technical. these two things will give you an edge over others.
Aptitude Questions and Answers is a good website to follow.
Search for only 2014 placement experiences.
Hope this helps ! All the best ! and if possible please get back to me to share your experiences once you are placed 🙂