ISO and Shutter Speed
It is tempting when shooting in low light to simply increase the ISO sensitivity on your camera (or use a faster film if you shoot with film). This may not always be the answer. Increasing ISO sensitivity decreases image quality. You will find that grain begins to appear. How visible this is of course depends on your camera or choice of film. An alternative is to set yourself to use slower shutter speeds. How much you are able to slow down your shutter speed without creating blurring due to camera shake depends on how steady your hand is. Try leaning against a wall or post, holding your breath and squeezing down slowly on the trigger. This is a method I use quite often and I have found that results improve significantly with a bit of practice.
Tripods
Using a tripod can have both technical and creative benefits. A tripod stabilizes your camera producing a sharp image when a long exposure is needed. It also enables you to reduce the ISO speed used to create a better quality image as discussed above. A tripod can also be used to create interesting effects should the scene contain moving objects. For example, a street scene with traffic passing by. Slow shutter speeds capture the motion of vehicles as they pass and the light trails from head and tail lights, adding life and energy to the scene. For many low light situations, a tripod is an essential piece of equipment and the only way of coming away with a decent image. An alternative could be to rest your camera on a flat surface if one is available.
Flash
Another method of low light photography is the use of flash. Using flash photography can produce quite different results. Like the tripod, and just about any other photography accessory, flash can be used to correct an exposure or enhance it. Set it to low power to fill in a dark area, or use maximum power for create highlights and high contrast effects. Using flash also enables you to hand hold your camera, giving you more freedom to move around your subject. Flash photography is not suited to all subjects though. If you are shooting say, a seascape just after sunset and pointing your camera out into the ocean, there is nothing out there for the light to bounce off and so it is lost.
Low light and night photography can be very rewarding. It does usually require a little additional equipment, but is well worth the expense. Taking pictures at different times of the day also puts you in the frame of mind to experiment, which is necessary if you want to improve your photography. Try things out. See for yourself what works and what doesn’t. You’ll be pleasantly surprised at the results.