The purpose of a first date is to get to a second date.  A first date is NOT the best time to determine if someone is a perfect match for you, as you likely won't know that on a first meeting.
  
Here are some sure-fire "first date killers" to be avoided in your quest for a romantic connection:
  1. Too late, you were late:  the most simple of tasks, showing up on time, is actually one of the most important elements of a first date.  Being late sends the message that your time is more important than theirs... and that's not sexy at all.
  2. Don't let your first impression be your last:  making a great first impression doesn't just apply to job interviews, it works on first dates as well.  Starting with a smile and a warm reception can lead to first date sparks.
  3. Being impolite:  being polite and kind to those around you; not just your date but the concierge, wait staff, bottle washers, etc., sends a message that you are a good and respectful person who is fun to be around.
  4. Being negative:  there is no place for negativity on a first date... focus on POSITIVE conversation topics.  Talking about how much you hate your job, or how terrible the food or service at the restaurant is, will likely make this first date your last.
  5. Bad phone manners:  taking a phone call, or even checking your messages, is bad dating etiquette.   Turning your phone off so that you can focus on your date is a modern dating turn-on.
  6. Don't be dull:  like most things in life, preparation in dating leads to success.  Think of a few good conversation topics or funny stories to talk about on your date... awkward silence on a first date is not a great sign.
  7. I can't hear you because I'm not listening:  good dating conversation should be a two-way street... actively listening to your date is a classic dating turn-on.
  8. All good things must end:  resist the urge to turn a positive first date into an epic and overly long ordeal.  Second and third dates are a much better time for a long dinner... after an hour or so, if the first date is going well, wrap it up and plan a second date.
  9. Don't wait for them to ask:  be proactive and bold; if you feel the date is going well, say so and suggest that you get together for a second date.  There is nothing more sad than not getting to a second date because neither party asked for it.
  10. Good endings lead to great beginnings:  a nice follow up email, or a quick call the next day, saying how much you enjoyed the date, is a great 'ending' to a first date.