1) Shooting high ISO ( 1600 film speed & higher ) handheld camera operation. Turn on your IS ( Image Stabilization for Canon ) & VR ( Vibration Reduction for Nikon ). Turn on NR ( Noise Reduction ). You can always cutnoise using the Photoshop filters or Noise Ninja. Higher film speeds means more noise and lower image quality. With a budget Nikon or Canon DSLR with a good quality sensor, you can get good night photos at ISO 1600. See my Camera Recommendations belwo
2) Shooting low ISO ( 100 film speed period ) on a sturdy tripod. Be sure to turn off the vibration feature of your camera body (Canon, Nikon, Pentax, Sony ) or the the VR or IS button on your lens. And use a remote toactivate the shutter mechanism or use the delayed timer. Even better use the mirror lockup feature in your camera. The last thing you need is vibration on your longggggggggggggg expsosure.