First things first: parking. Make sure there's some reasonable safe parking close enough to where you want to shoot to allow you haul in your equipment. This is especially important since you'll want to have a good tripod with you. The exposures can run several minutes unless you really crank up the ISO.
Second things also first: safety. I feel pretty comfortable walking around solo in the park at night, but if you're not, bring a friend. In addition to any human threat, keep in mind that many animals are nocturnal, so know the fauna in advance. I don't normally run into anything scarier than a skunk or a raccoon.
You'll also want a good flashlight and backup batteries. Besides the obvious reasons for taking one, if you have an object near enough in the foreground, a flashlight will let you see it well enough to adjust the focus. In these conditions, auto-focus probably won't work. If you're there with a friend, have him or her hold a flashlight up to an area you want to focus on.
There are differing opinions on this, but I always use AWB for the white balance. I can barely see a lot of the objects I shoot, so who's to tell what they really look like at night ?
Then just look around. Is there an interesting reflection of the moon or outdoor lights ? Dramatic cloud cover ? Running water ? Scary treetops ? If you're patient you can capture something spectacular.
- Get a cable release or remote which can lock, then go into bulb mode if necessary.
- You may need to make several attempts before you get the correct exposure time. You can get a good estimate by cranking up the ISO for a test and recalculating for the ISO you actually want to shoot at.
- Even with the flexibility in exposure time, you may actually need to turn up the ISO. Some cameras have an upper limit to exposure time even in bulb, and besides, the exposure times can get high enough to cut into times for other shots, or your sleep.
- If you have a close enough foreground object, you may want to experiment with the camera flash or "paint" the foreground with a flashlight. You'll want to set the exposure time for the background.
Have fun, and stay safe.
You can find product designs based on my outdoor night time shots in my zazzle store. If you have a product in mind but don't see it, just leave a message on the store wall or product page and maybe I'll design it for you!