How to prepare for aptitude tests for placements

Let me start by categorising the "IT companies".According to me, there are 4 categories.1. Extremely Brilliant companies (Facebook, Google types).2. Excellent ones (Adobe, Oracle India, Goldman Sachs).3. Above average companies (which offer anything between 5lacs - 10 lacs).4. Average companies (where 70-80% of Engineering folks are placed. Egs are