Totally be yourself...your 'soulmate' wherever she (/he...don't like to presume!) is, will accept you for who you are, so trying to act any other way other than yourself won't get you far (it may get you laid though!). Ask general questions that they can elaborate on and chip in with a few quick things about yourself, like your hobbies and interests (if you play an instrument, your favourite film/music, where you've travelled...). Never been 'speed dating' but I assume that speed is an integral part of the experience which won't allow you to jabber on, SO make time for them to speak (women LOVE to talk and will appreciate if you can 'share' the allocated talk time and not just be on the receiving end of some bore talking about himself the whole time!). Good luck, have fun and keep an open mind. Also, try not to get your hopes up that you'll meet your perfect match...you may end up being disappointed. Just see it as a fun night out, relax and JUST BE YOURSELF! Then if you actually do hook up with someone, it will be a pleasant surprise! :)