People continuously make you aware of the various expectations of when the first kiss should happen. Do not pay attention to it. What's most vital are the small things that will help you to know specifically when that moment has arrived. Give thought to the general atmosphere of the date (night or day), whether there's a clear mutual attraction and whether or not she actually wants you to kiss her. The little aspects will be the largest decider as to when the right time comes.
The media turns the first kiss into something it is not.
Watching intimate films, along with a lot of various media, the first kiss is frequently dramatized. The two people are obviously attracted to one another, it's been a great day, and they're lying on a beautiful, well-lit beach as the sun sets. While it would be amazing for a moment like that to transpire, usually when on a date you get minimal opportunity to kiss your date. Forget about waiting around for the 'perfect' view with the 'perfect' environment, be spontaneous, and seize the opportunity.
The first kiss involves expecting the best but being wary of the worst possible exit. From time to time, revisit the events of the night and think; 'If a moment came right now, would she want me to kiss her?'. If you think the answer is yes, stop pondering it, because otherwise you will only end up discouraging yourself, and wait for an opportunity to present itself.
If it is your first date and a moment never came up, do not worry about it. Hold out for your next date. If it's your second and it does not happen, think about the day and what you could've done for the opportunity to happen. If it's your third date and there have been no signs of a want for you to kiss your date, keep in mind that she's on a third date with you, which means she is obviously interested. Take that for what it is, and kiss her when the slightest opportunity comes.
Women enjoy a guy being spontaneous, and will openly accept the kiss (in most cases).
Some things you can not control, and when it gets to that point, all you can do is be confident, and prepared. Men with female friends have a better understanding of women, and can read their indicators a lot easier too, which in turn makes it a lot easier to read women, and communicate with them overall.