Ranker has listed the "Top 10 Facebook Mistakes to Avoid After 1st Dates" ... and as a single guy, trust me -- it was well worth the read.
1. Friending TOO SOON -- "It was just one date. No matter how magical and rainbow-filled it was for you, maybe your date was bored out of his or her mind. You don’t know if you’ll ever see this person again. If you weren't already friends on Facebook, there's no reason to take that step now."
2. Facebook Jealousy -- "After a first date, you start to wonder if you're the only potential paramour in your date's life. You start to see photos and comments on Facebook in a whole new light. When pictures are posted from a night when your date said they were too busy to see you, you start wondering just who the other people in those photos are. And why is there someone who always likes your date's statuses? Sure, they could just be friends, but why is this friend so involved in your date's life?"
3. Creepily Liking Old Facebook Photos -- "They may be public, but going through them and then liking a hot picture constitutes the first order of creepiness. Leave compliments for when they dress nice for you in real life."
There are seven more -- click here for the rest.