Yay, something I know a fair bit about!
Alright, well, shooting day for night is very tricky to have it come out actually looking like night(obviously, the brightness of the sun generally gives it away).
As for things you could do in post, you could just color correct it to give it a blue cast, adjust the various color levels until you get something you’re happy with, then drop the brightness and up the contrast slightly.
You best bet, if you can do it, would be to shoot at night and light it properly. That’s the big tell of a student/amateur film, poor lighting. The other one is poor sound.
A bright HMI light from one direction will be your source of “moonlight” with a blue gel over it. Then a less bright light from the opposite side will be your highlight(for best effect of highlights, try to use the color from the opposite side of the color wheel from your key light(which, in this case, would either be an orange gel or just a tungsten light(if your other light is a HMI daylight balanced one). Finally, assuming you’re in close, you can use a third light to fill in only the faces of your actors(a softbox or a paper lantern would work well).
But, if you haven’t got any of those fun toys/the money to rent them, you can always try to shoot and do it all in post(giving the footage a blue cast, messing with contrast and brightness, playing with the color curves, etc).
One thing to remember, never EVER up the gain on the camera unless you absolutely have to. It introduces all kinds of noise and that leads to artifacts with the way DV compression works which appear in the form of dancing blocks, which if this film is going to be shown on a screen larger than a 27 inch TV, will only get more and more glaringly obvious as the picture gets larger.
Also, unless you’re using one of the various prosumer SD or HD cameras(sounds like, if the department has anything good, they’ll either have Panasonic DVX100’s or Sony PD150’s/VX2000’s, unless they went for multi-lens set ups and went with XL1/s/2’s), don’t try to shoot and frame to letterbox since, assuming you go to say 2.35, you’re effectively removing all kinds of vertical resolution from your picture(this is the reason that the original Star Wars movies, when viewed on the older letterboxed VHS tapes, the stars dance and twinkle and disappear, they’re low resolution).
SD NTSC video is 720X480 pixels. Cropping to, for example, 2.35 wide will cut your vertical resolution by about 180 lines. If you really want that wide screen feel, I’d suggest shooting 16x9 or shooting with an anamorphic adapter for the camera. The DVX has a nice mode called “squeeze” that is anamorphic, the PD150/VX2000 and XL1/s crop down to wide, and the XL2 shoots native 16X9.
What else… um, well, again, if you can shoot at night, try to use existing light and simply add to it. For example, if there’s a street light somewhere near by, add lights near that which are pointed towards where you’re shooting.
Also, if you do any of your own lighting, be sure to shoot out that light set up as, more than likely, you’ll need to change it for different shots. Also, be sure to shoot out the various camera angles. It’s best to finish them up so that you’re not running around setting up the same positions over and over again.
Best of luck on the shoot, you should post it up so we can see it when it’s finished!