Assess how the evening went. As it winds down, it shouldn't be too hard to tell if both you and your date had a good time, as any awkwardness would have been obvious. Simply think back to the conversation, the amount of laughter and whether there was any semblance of a romantic spark. If things have gone well and there's chemistry there, you're in good shape for a smooth, pleasant goodbye. If any or all of the above are lacking, then you shouldn't force anything in terms of a kiss; just go with the flow and politely bow out.
Dismiss any preconceived goals that you may have. If you decided that getting a goodbye kiss is the only acceptable ending, then you put undue pressure on yourself. Plus, your date will more often than not sense that you have an agenda, which diminishes the romance of the moment. Vague and cliched as it may sound, it's important to just be yourself.
Know when to end the conversation. If you're at your date's front door, you want to avoid gaps in the dialogue. Again, don't force the issue. If the chat tails off, mention that you had a great time and that you look forward to doing it again some time.
Ask your date for another date if you're interested in seeing her again.
Maintain your composure, no matter how the goodbye goes. A relaxed and confident vibe will serve you well. If the conversation -- and the whole evening, for that matter -- is pleasant, it's acceptable to move in for a small kiss. Even if you end up misreading the signals and get turned down for the kiss, simply smile, say you had a good time and bid farewell.