Depending on what you are trying to achieve will determine your aperture but at night, I tend to want a high f-stop such as f/13 to give me good depth of field and allowing the shutter to stay open for longer, so giving light trails if you have cars with their lights on driving through the picture. However, the settings will be very much your choice for the effect you are seeking to achieve, but...
... critically, always shoot 100 ISO if possible or else you risk significant noise in the dark parts of the picture (which are many at night). There are times when ISO 100 isn't practical such as on a windy day when longer exposure times risk camera shake due to the gusting wind even when on a tripod, or, as was the case with me in Oxford, when I got past midnight and really wanted to wrap the evening up but seeking to grab a few last frames went to ISO 200 to halve my shutter time.
After each exposure, check too the back of the screen (and histogram) to see if your exposures are right; at night, trial and error is very much how you get the exposure you want, and there's no right or wrong here, again, what look are you going for, dark and moody or eye popping vibrancy?
Shooting at night in London, the major landmark buildings like the Houses of Parliament are lit up purposefully so they look good at night. In Oxford, the key buildings like the Radcliffe Camera or Sheldonian Theatre are not lit up at night and therefore rely entirely on reflected street light. This poses no end of problems, not least, the streetlamps throw out a dirty yellow light that coast everything.
The picture below is taken straight from the 'in camera' RAW file and is without doubt pretty nasty. From the building to the pavement to the road, everything is yellowy orange and it is hard to think there is a nice photo there struggling to get out. Meanwhile I have to take responsibility for the angle being out by a few degrees but this was close to my last picture of the day and I was admittedly beginning to fade by this point. But most importantly however, and why it's a keeper, this picture is super sharp: focus is everything as it is the one thing you can't correct after the event.
That's the power of shooting RAW.
And of course, you get some delicious light trails from passing vehicles, and some of these from my night in Oxford are shown below.