First of all, I will say that truly excellent advice has been posted thus far, by people more experienced, by far, than me. I will contribute just a bit, because much of my limited experience has been gained shooting at night.
Going back to the original post, the mentioned recommendation to open the aperture to the lowest possible F-value is quite right, and spot on - open the aperture to the lowest value that gives you the depth of field you need, which is different than opening the aperture the lowest setting mechanically possible. As dubaiphil mentioned, shallow depth of field is not a limitation when the subject is at or near infinity.
If one needs a significant depth of field in low light, and therefore must stop down to f/11 or more, then a tripod becomes immensely important. I shoot crime scenes at night, and to show as much detail as possible, with things all scattered about, will stop down to f/16, or even to f/22 or more, and use a tripod and remote release. (When I manage to misplace my wired remote release, or am using two cameras, there is the option of setting the shutter to release after a 2-second delay.) If one's camera cannot record an exposure longer than 30 seconds, then, one may have to up the ISO, but if there is a bulb setting, the ISO can be kept low.
An interesting thing about long exposures is that people and animals can actually walk through your imaged area, and if they remain in motion, will be virtually or completely invisible in the finished image. This assumes they are
not carrying any form of illumination, such as a flashlight (USA) or torch,
for those speaking the King's English. Of course, moving vehicles and aircraft
will leave interesting trails of light across the image.
Canon 7D/5D/40D/1D2N; Nikon F6, D700, FM3A, & Coolpix A; Canon 40mm 2.8 STM, 135L, 50L, 35L, 50mm 1.8 I, 100mm 2.8L Macro, 10-22mm EF-S, 28-135 EF, 400mm 5.6L; Nikkor 50mm 1.2 AI-S, 50mm 1.4G, 50mm 1.8D, 16mm 2.8D Fisheye, 180mm 2.8D, 100-300mm 5.6 AI-S, 18mm 2.8D, Voigtlander 90mm f/3.5 SL II