There are 3 things that are important to use when you use a high end camera.

1) Shutter
2) Aperature
3) ISO

Shutter is how fast the eye opens and closes; leave it open longer at night for things like trail lights or to catch a drop of water falling from the tap.

Aperature is how much light is allowed into the camera to take a picture. The more light allowed in allows for a low light situation to be brighter but you pay a price as the more light you allow in a dark situation you run the chance of getting blurry pictures

ISO is the amount of light the camera can absorb. ISO 50/100 is ideal for sunny days or being outside during the day and if you have a UV filter (which you should if your lenses can take it) to help cutting a lot of the brightness down.