After your date responds, say something to acknowledge him/her, elaborate on the conversation, give your own opinion and share your own experience about given topic.
People are usually interested in what they have to say, so try contributing to the given topic as best as you can.
You probably want to reveal something about the personality; great types of questions are those starting with "what would you do if...".
Remember you are at the speed dating to have fun, meet new people and have a pleasant chit chat; everything else will spring out from that.
Don't forget that the non-verbal communication plays maybe even a bigger role in choosing next potential date than the verbal one.
You might think that small talk is superficial and meaningless, but don’t be too harsh in your judgement: it can play in important role in human relations on a daily basis, and it’s a great way of getting to know people the first time you met them - unless you think that Freud’s Interpretation of Dreams is a better subject for a first discussion than what was on TV on Saturday night.
It sometimes pays to take the easy option, and, if everything works out, you’ll have plenty of time later for deep and meaningful discussion.