Hello,
Search the pattern of questions here that they ask on aptitude test .
Once you have cleared in aptitude test , make sure you are good with few subjects that you studies during your UG .
Eg . Programming , Networking , Data Base etc…
While you attend the interview try to pitch in those topic that you know in a wise manner.
This will help you to make the interviewer ask questions from those topic and channelize the flow of interview .
Best wishes .