i would suggest these following
1) have a background understanding of the company you are going to get the interview done
2) prepare some questions to ask (should be related to the company latest progress of move) and provide your thoughts and why
3) prepare some topic of discussion that you know best and from the questions they asked try to divert to this so you can express your view freely and impressing
4) if you are interviewing for a technical job, then impress them with the technical skill

all the best