>>2688410After you get that down or if you want to shoot things in motion, start looking into S (shutter priority) mode. This will let you pick a shutter speed that gets you the amount of motion blur (if any) you want.
Basically A (or Av)=depth of field is your most important creative factor for the image
S (or Tv, depending on what brand you shoot)=motion blur/freezing motion most important to your shot
M=lighting that fucks up your automatic meter
Another good mode to learn is P which is like a kind of halfway manual but not really.
One thing you really, really need to spend time to understand and experiment with to make sure you understand is the different metering modes. (Spot, evaluative metering, partial, or whatever other settings your camera has). The meter on modern cameras is damn smart, but it's a computer so it's really stupid at times. Knowing how it works means you know how it'll be stupid, when it'll be stupid, and how to correct for that.