Getting your DSLR off auto

Most beginners who buy maybe a Canon Rebel __ or Nikon D__ DSLR have their cameras on Auto and never really stray from it. Or some people use the pre-set settings (those little pictures). Now those work fine, but to really unlock the features of your camera, you really need to venture to the other "letter modes" - For Nikons (since I have the pic): M (full manual), A (aperture priority), S (shutter priority), P (semi-full auto). I'm gonna give you a rundown of 2 of the modes I use the most: A, and S.

A: What is it? [controls how big the circle opens up on the lens]

When to use it? [When you want control the focus blur of your backgrounds or dark situations when you don't want to use flash]
* indoors without flash
* natural light portraits
* pictures of stuff where the background is blurred or fades to a blur.

S: What is it? [controls how fast the camera takes a picture, the faster the less light but less motion blur]

When to use it? [The slower the speed, the more light gets recorded but it becomes very sensitive to even the slightest movement, which is why you have blurry pictures]
* fast paced sport events
* teacup ride in Disneyland where you want to motion blur the background
* smooth water effect in rivers, waterfalls, etc.

Here's the great part: you choose the A (commonly known as F-stop) or S and the camera takes care of the rest. You just pick what your priority is depending on what the situation you're in calls for. The shutter speed is camera dependent, while the aperture is lens dependent - the lower the F, number better (and more expensive). More later with examples.