One adjustment that amateur photographers using digital equipment forget to set is the White balance.  Unless you are shooting in Raw format, setting the white balance is extremely important! 

The white balance sets the point at which the red, green, and blue sensors will maximize their output to create white.  Our eyes adjust to different light levels automatically, camera makers try to emulate that using auto white balance.  Using auto white balance to shoot indoor and outdoor wedding photos is going to mean that the skin tones will not remain consistent between shots due to the change in relationship between the ratios in the red, green and blue light mix that is needed to keep the white dress looking white in the varying light conditions.  Differences in skin tone consistency are often more perceptible to us and locking the white balance makes at least one variable  that causes them go away.

White Balance can be looked at as if it were color temperature.  Bright sun is about 6,000 degrees K, incandescent lights are often 3,200 degrees K.  Many  cameras allow you to set the color temperature of your white point anywhere between 2,500 to 10,000 degrees K.  My  own preference when shooting (I shoot in Raw which means I can adjust this later should I choose) is to leave it at 5,000 degrees K.   If you are not shooting in Raw mode, it should be set to accommodate the actual light you have on hand so as to let the camera create the best possible image for you.

Setting the white point temperature to a lower temperature increases the amount of blue in the final image.  Jpeg shooters can use this adjustment to create a more dramatic sky in their landscapes.  Shifting the color to a higher than normal setting increases the red, something that can create a better monochrome print at a later time.  Look at your image and adjust your white balance to make what you see match what you want the image to be!