Night shots really fall into two camps in my opinion... low ISO or high ISO.
A lot of what I do, where stars are not trailing, is a high ISO shot.
This entails several key parts that together can be a real stress test on your equipment and their capabilities. For these types of shots, it's all about getting as much light on your sensor in as quick of a time frame as possible.
First, in order to keep stars from trailing, means you need to keep your exposure under 25 seconds or so. This is a variable because the wider the lens, the longer you can expose for. It's also dependent on your camera sensor - crop camera vs full frame - crop cameras will not be able to expose as long as a full frame camera. Also, the direction you're shooting in can affect this as well. Generally pointing towards polaris will allow you to increase your exposure time a bit versus pointing towards the southern hemisphere which will require shorter times.
The moon phase is also very important. For Milky Way shots, you want a new moon, so that the skies are totally dark.
But, you can shoot on almost any night in any phase, it just changes things a bit. If you want distant landscapes to show up well, you'll need
some moonlight. For those kinds of shots, I generally like waning and waxing gibbous moons (about a 1/4 moon sliver is really ideal usually). This will give the sensor enough light to pick up from the scenery, making it visible - while still allowing for good stars to show. Capturing the Milky Way when there is a moon, can be be a bit tough, unless you're in very dark areas.
The lens you use will affect things as well. Since you'll be shooting at infinity, it is not a big deal to use a large aperture, so you'll want to shoot at ƒ4, or larger if at all possible. You can shoot at higher apertures, but of course you're not going to bring in as much light as you would at ƒ2.8 or ƒ1.8 etc...
Crank your ISO as high as your camera body will tolerate without getting absolutely horrible grain (grain can be handled with noise reduction in post processing and will help this a good bit).
For foreground focus, I generally know what my lens MFD(minimum focal distance) is and what the hyper focal distance is and then frame my shot accordingly. I've also memorized the spot at which my lens is at true infinity. This is important to do before you go out in the dark, as you won't be able to use AF and trying to get infinity in the dark can be really tough sometimes. So, if you figure out the spot on your lens scale that is the lens's true infinity and then memorize that spot. That way, it makes things very easy when in the field. A set it and forget it type thing.
So, in a nutshell - what I try to do:
Point towards the north if I can.
Set my ISO to 1600, 2000, 2500 etc..
Lens aperture set to ƒ2.8 minimum.
Keep my exposure under about 25 seconds
Of course, you're also using a tripod and remote trigger/shutter release.
Now for the artistic stuff....
A lot of the shots I do, include a foreground element, often artificially lit or sometimes with moonlight. A foreground element is really important, as it gives things a sense of scale, and it helps for composition. The night sky is beautiful, but it can be fairly dull, if there is nothing but sky, esp at wide angles.
I often do a bit of light painting on the foreground element. I use speedlights and diffusers just as you would for portrait photography, just that I'm shooting a car, or a tree, instead. Beware though, since your camera is setup to suck light in like a vacuum, any light you provide will not take long to overexpose your shot.
I tend to like my WB on the bluer side for night shots(often using Tungsten mode), but this is purely subjective and will depend on the scene. Of course, if you're shooting in RAW mode, this isn't a big concern because you can change it later in post.
I will be going into these subjects in more individual details later, so please watch for those soon.
If you have any questions or need help, please don't hesitate to ask in the comments below.