Now that your camera is set up, the batteries are fully charged, and you know exactly what you are going to photograph, you have several layers of warm clothing, a mobile phone, sturdy footwear and all the paraphernalia packed away in your camera bag..........off you go......
Wait....what are you going to photograph exactly? Where will the Milky Way be (or whatever night sky feature you want to include in your photograph)? Does the position of the Auriga constellation in the sky allow me to take a photograph with that trig point as a foreground? In the dark, can I safely get to this location? What is the moon phase? When will the moon come up, and from which direction will it shine?
All these questions (and there are plenty more as you will very soon discover) need to be answered in the harsh light of day. The success of a nightscape image is directly proportional to the legwork and planning you do beforehand. Although it is obvious, it is dark at night. Your senses are heightened, but our eyes are pretty poor in the dark. Scrofflings and scrabblings in the undergrowth can be unnerving when you can't see what is making those noises. Ditches are virtually invisible, protruding branches seem to reach out into your path to trip you up.........
Perhaps the best first step is to sit down at your computer, or preferred device, and consult Stellarium. For the desktop, Stellarium is a free downloadable application and it is simply brilliant! Available for Mac, Windows and Linux, Stellarium allows you to input your location and any date, whether now, past or future, and view exactly what will be in the night sky. There are additional navigational and positional aids to help you plan exactly where stars / planets / galaxies / meteors / satellites will be. There is a paid version available for smartphones (both iOS and Android) and this is also very useful and well worth the few pounds investment. Be warned........this app is addictive!!
Another app which is well worth the few pounds cost is Photopills. Photopills is probably best described as a Swiss Army Tool for Photographers, as the features it offers are extensive. It is excellent for planning Milky Way compositions as it shows you when the Milky Way will be visible, and at what angle.......again, for any location, time and date.
There are literally dozens of tutorials available on YouTube, so there is no need to cover any instruction on usage here. However, be assured, these are useful, if not invaluable, apps for nightscape photography.
I cannot stress enough the value of scouting your chosen location during daylight hours. All sorts of hazards can be assessed in the clear light of day, and planned for, prior to your nocturnal excursion. Where will you park the car, where does the path cross the ditch, how difficult is the walk, what other factors / obstacles are going to impede your photographic efforts - all these things can be understood in the light of day - but not at night. Be warned!
A reliable weather forecasting app (if there is such a thing) is the final ingredient to successful planning. I use the free app Clear Outside, as it gives not only weather forecast information, but also cloud cover information, temperature, wind speed and direction and whether or not the dew point is going to cause a problem for your lenses.