If she does join you, you are in a great position to present your best side to her. Your eye contact and closeness should be open to her, but not crowding or threatening. Again, if she is having a good time, she will be open to contact. Remember, single women enjoy sensuality. Instead you alertly perceive that the evening is still going well and positive, so you politely explain that you have to go, assure her that you had a great time, and tell her you'll have to get together again.
Most men seem to think that if they prolong the date enough, they'll get the girl in bed.
As the evening drags on, the mood of the date starts to drop and the girl ends up having to announce it's time for her to go. By ending the date before she does, you surprise her and set yourself apart. You imply that you are hard to get, and not desperate. And believe us, if the girl is interested in going to bed, you'll know it. She will make her sexual interest in you known to you.