The best way to know that you've achieved that goal is when you find yourself being invited back to her place, hopefully to spend the night.
Most guys think it's hard to actually convince a girl to spend the night with them.
Why try? Why not get them to invite you to spend the night instead? The thing women hate the most is someone thinking that they're easy or that they're a slut.
They want sex as much as we do but they can't stand someone thinking 'badly' of them.
Keep this in mind while you're headed for your goal.
Make her feel special.
Make her feel relaxed.
Let her know you respect her as a person.
Don't make obvious comments about having sex.
You both know you want that but women love word games.
They love verbal foreplay.
Their minds fill in the blanks so be a little vague on sexual matters.
Be sure to insinuate toy with the concept verbally but keep them guessing.
It heightens their sexual desires and makes you much more of a score for them.
If it's time to part and she still hasn't invited you back to her place you might teasingly let her know that you'd like to spend more time with her.
By pulling out the 'puppy-dog eyes' to let her know you're clearly teasing you can say something that makes her know this.
If it fails to work at the very least it should get you a quick date where you'll have a second chance.
Remember, pressurizing her will backfire on you.
Allow her to the freedom to take her time.
Just as when she's having sex she'll want to take her time.
Give her time to reel you in; to invite you back to her inner sanctum.
After all, if you have the patience for a fish when you're fishing this catch ought to be given even more time! ;)