I can't seem to get a handle on how to seal the deal with someone at the end of the night. Even if everything seems to be going great, SOMETHING always seems to happen.

For example, last night I knew for a fact this girl was interested in me (based on her insisting I come back to her place after the party and talking to me A LOT throughout the 5 hour party. By the time we got to her place, she was visibly tired (and too drunk for me to feel comfortable pushing the "let me stay with you" envelope). We sat and talked for a few minutes, and when it was time for me to go ALL I wanted to do was kiss this girl. When it came time for me to walk out the door, I just hugged because I could not sense if she wanted me to kiss her (or if that would even be ok if I tried).

What are the signs that generally point to the "at least give it a shot" door?