Go out on a full moon, you will be surprised how well you can see once your eyes adjust to the low light conditions. New moon and pitch black is completely different story.
I boat on Mead, Mohave and the Colorado River and don't have issues running at night, but I'm familiar with the areas I'm boating and know what to avoid. If in doubt or if something doesn't feel right - cut the throttle! You never know what you'll find floating around out there: 10' long doug fir 4x4, tent, canoe, huge tree branch, boat no nav lights, are things I've found floating around at night.
I don't 100% trust my electronics at night, especially on fluctuating reservoirs, I use them as a reference to run the main channel. Mead is about 100' low and my charts are for near full pool, so a high spot 75' deep on the chart is now an island. I have also seen many unmarked reefs with no buoy, or channel marker/navigation lights burned out. Even if idling along, keep your wits about you as your vision is highly diminished and the water will look black, I've been startled a couple of times when I wasn't paying attention close to shore....
Have more than one light source on the boat. More than once my Qbeam has gone bad and I've had to use a flashlight... The trick to using a light while night boating is to not "light up" the boat hull with it's reflection, hold it high and shine it upwards towards what you want to look at, so your eyes are not catching the reflected light off the hull. Your night vision will still be ruined to some degree, but not nearly as bad as if you're looking at a lit up hull. When coming into a harbor, I do the opposite, shine the light into the water at an angle to bounce the light beam, so I'm not blinding everyone on shore.