How do you know a girl wants to smooch?

Well... when we give you that "look"... when we smile at you and lean in closer... when we invade your personal space... when we find ways to brush up against you... when we fall all over ourselves to make eye contact and laugh at your jokes... it's a pretty safe bet that we want you to kiss us.

Make this really easy for the guys:

1. Position yourself within smooching range. 30-40cm is best. This must be done in a "suave" manner, ie, don't make it totally obvious that you're lining up for a kiss.
2. Stare into her eyes. This must be done under the guise of "making eye contact" during the conversation.
3. Conversation lulls, non-awkwardly. Usually safest to let her have the last word.
4. Count to five. Slowly. A faint smile and slightly more opened eyes on your part helps to prepare her.
5. If you're still silent, incline your head minimally towards hers. Inclination change should be no more than 5 degrees or 2 cm, whichever is smaller.
6. If she wants to smooch, she'll catch the signal and respond in like manner. Bonus points if she closes her eyes as she goes in for the lip-lock. This indicates a willingness to trust you. Don't mess it up.
7. Slowly bring faces together, tilted properly so that noses don't collide (which can be disastrous in the "trust" department). Keep your eyes open long enough to properly align your lips with hers (since her eyes will probably be closed already). After lips are initially positioned and in contact, close eyes. Experimentation with further action is left as an exercise for the reader.

This process has worked successfully (executing desired smooches as well as avoiding undesired smooches) several times for me.

I feel like i have to add something here.
I've had some girlfriends over the years, some one-night-stands, and many, many disappointments. And if you ask me, feeling much too old and a bit wiser than i would like myself to be, it's just that for sure you never can tell.
It is quite simple about us guys, maybe, were just too simple-minded, but if a guy wants to kiss a girl, the girl knows it instinctivly. Every other person 'round knows it, if he or she looks over to him.
But for the girls, it's not that simple. Everything mentioned above can be a sign that she wants to be kissed, but theres a fifty percent chance that she does not want it and is just a nice, cute (read: bitchy, man-murdering, soul-raping) person, which directly explains why every attempt to kiss her will lead direct to disaster.
I've been in this situation for at least 4 times, and wish i would have never been.
It's all in the hands of fate...