Honestly, to take outdoor night exposures, what I mostly do is use a tripod. I aim for ISO 100 (200 if things are /really/ dark), f/11 to f/14, depending on my whims at the moment, and then 20-30 seconds of exposure. If you have live view (or some other way of locking the mirror up, to avoid shutter-jitter) and either a remote trigger or a timer that you can use to ensure you're not touching the camera when the exposure starts, make sure to use them.
But really, the short form is 'low ISO, small aperture, long exposure, and don't let the camera move if you can avoid it.'
If you're shooting JPG, toy with your white-balance to make sure things are cooler; live view works well here. If you are shooting RAW, you have a little more freedom in
post-processing night shots. I've discovered that the ideal when you can is to get that cool, twilighty blue gradient in the sky; the effect can be very powerful.
Hope that helps!