Manners and/or Kindness

Thank the other person for the date - always, without exception.
Good manners are still in style. Well, not necessarily good manners - but common sense. Human kindness. That sort of thing is always in style.

Focus on the Other Person - pay attention to your date.
No wandering eyes. No preoccupation with old relationships, work, bank robberies.
Be THERE.

Listen actively to what your date says.
Don't interrupt. While your date is talking, don't spend time thinking about what you're going to say when it's your turn.

Attitudes and Habits - stay positive.
Don't complain on a first date.
Be cautious about alcohol - if you drink heavily, you're not going to be at your best.
If your date gets swacked on your first date, it's not necessarily due to nervousness.
He or she is likely to be a heavy-drinker, at best, and could end up drooling on your new, pressed clothes as you shovel him or her into a cab