There are some key element for GD/PI Preparation: Know the process for GD/PI. Work on your skill & Practise till you gain confidence and are able to perform well. Improve your general awareness by reading newspapers & magazines. As PI test you should have self awareness & your subject knowledge.You should revise important concepts at least two major subjects and think about their real life applications.

Type of questions you can prepare:

HR based this relates to how clear your future goals are like Why mba? why this college? etc., Your past academics based, GK based from current events, opinion based on politics and recent movements. The key is to keep calm under pressure and answer well even if you face a bad question.

Good Luck!