If you're shooting outdoors at night, one of the best tips I can give you is to not shoot with one of your camera's standard modes, like aperture priority (A on a Nikon or Av on a Canon), or any of the preset modes, like landscape or portrait. Those all work pretty well during the day, but shooting at night, and getting the night sky to be that really dark blue or black that you're seeing with your eyes, often isn't going to happen with one of those modes, because they'll make the whole image too bright. After all, your camera doesn't know it's night, so it's just doing its job of trying to make a proper exposure. That's why I feel that the real secret to shooting at night is to shoot in manual mode. To do that, you'll need to use the meter inside your camera's viewfinder (this is so easy to do, you'll be amazed, so don't let this freak you out one little bit). So, switch to manual mode and dial in a starting shutter speed (at night, you'll be on a tripod, so try something like Image of a second to start). Let's also choose an f-stop to start with. How 'bout f/8? Okay, good. Now, look in your camera's viewfinder. On a Nikon, the meter shows up either on the far right or bottom of your viewfinder; on a Canon, it appears at the bottom of the viewfinder. There's a big line in the center of your meter, and then little lines that go above it and below it (or to the left and right). If you see lines above the line, it means that if you shot right now, your shot would be too bright (overexposed), so try moving your sub-command dial (or quick control dial), which chooses the f-stops, until you see those lines go away (which means—perfect exposure). Now, that may be correct (technically), but if that night sky isn't nice and black (or dark blue), keep turning that dial until it underexposes.