As said by Vlad, there are several format of event possible. In any case I recommand you to behave as a contributor and not a spectator. You are here to learn about the firm and give them the will to call you for an interview. So you'll find below a listf of the tips I used back in time :
- Behaviour : somehow candidate are always considered on how they would do in client facing situtation. Be open, willing to discuss. If you are at a networking event, its to meet people, so don't hesitate to engage conversation with anybody from the firm by simply introducing yourslef or asking question to the person based on his own intro.
- Ideas : don't hesitate to share your ideas, participate in a case resolution, and stay as structured as possible in your arguments. In case you are involved in a group discussion, leverage as much as possible elements brought by others to show your ability to work / act in
Hope this will help