One of the most fundamental things every new photographer should learn is how shutter speed, aperture, and ISO interact to produce an exposure. This great video will introduce you to the three parameters and how each of them determines your overall exposure.
Coming to you from Apalapse, this helpful video will show you how the three fundamental exposure parameters interact to produce an image. Quite often when you're shooting, you'll have to make both a creative decision in how you want to combine the three to make a shot and a practical decision that your shooting environment imposes on you, and the successful photographer is one who can balance their creative impulses with the environmental limitations. That's why it's so crucial to become so familiar with the settings and their effects on your photos that they become instinct and you can quickly dial them in in any situation, as a camera's auto mode doesn't know your creative impulses and simply tries to create a balanced exposure. Personally, I think one of the most important lessons is to remember that it's always better to have a high ISO photo that's sharp than a low ISO photo that's blurry. Don't trade off so much shutter speed that you introduce camera shake or subject blur. Check out the video above for the full rundown.