Smile. Experts the world over agree that a smile is probably your most powerful asset. It is the international signal of friendliness. It actually helps to make you more attractive and approachable. It lowers barriers and shows an intention to be friendly.
Dress to impress. You have only seven minutes to impress your date so you should make every effort to ensure that your appearance will impress.
Be genuinely interested in what they might have to say. It is important to make the other person feel good about themselves and want to talk to you. It's not always about being entertaining and making them laugh but obviously if you both have a similar sense of humor then the rest should be easy.
Try not to be too personally intrusive especially as an opening line. It would probably be more appropriate to mention something about the event or surroundings etc.
Try not to offer information about yourself unless you are asked. However you could prompt questions by offering hints or by asking the other person the same question. They will normally reciprocate.
Try to establish areas of common interest.
Be complimentary about the other person, but be genuine.