Be ready for a talk
Speed dating requires fast communication skills. You cannot keep silent and be quiet when there are so many other people trying to get each other. Know the person as quickly as you can by talking about something in general to see how well you click and understand each other. Decide on subjects to talk about before the event.
Share numbers
If you see that you have met someone intriguing and you feel like continuing getting the person, then feel free to ask for a number. You can also ask for any other way of contacting the person: messenger ID, e-mail, Facebook or Twitter. You just need to have something to help you get in touch after you say bye.