Cropping:

• When cropping in Lightroom the pixels should go down because you are cutting some pixels out.

• When cropping in camera (step the camera closer to the people, or zoom in a bit)- you wont lose any of the quality.

• When cropping in Photoshop or Lightroom link together the resolution, the height and the width. (When you UN-link the resolution (the 300) from the height and width, the computer is filling those extra spaces in with random colors and destroying quality and integrity in the image). All three of those things need to be linked so that when you move resolution down a bit, your image gets larger in inches.

• Max resolution of say 26 megs is the full frame of the image that is taken... once it is cropped post production in a program such as Photoshop or Lightroom, you are throwing some of that data away... the smaller it is cropped, the smaller the megs of that cropped image.

Color Correcting (White Balance)

•To color correct in Lightroom…

•Open the gray card image that you captured on the same day in the same setting as the family you are processing.

• Open an image in the Develop module.

• At the top of your Basic panel are the white balance adjustment tools.

• To balance the image using the White Balance selector, click on a pixel that should be neutral grey – not white or black.

• When you do so, Lightroom will adjust the image so that the selected pixel is a neutral grey and, as a result, all the color in the image will change. 

• You should be aware that adjusting image white balance is to an extent a subjective assessment – so there is no one value that is “correct”. There are, instead, a myriad of different results that can be achieved so look for one that is it pleasing to you.

(Info here sited from: this website)