Exploring Editing in Lightroom

I've only had Adobe Lightroom for about six months and I have a lot to learn about using it efficiently and effectively.  Yesterday I sat down and read more about using Lightroom presets and brushes to edit images.  Lightroom presets are steps that have been recorded and let you easily make changes to a picture, like turning it into a black and white image or warming it up.  Lightroom brushes let you make localized changes to an image, such as whitening the eyes and smoothing the skin. 
I learned that when you edit an image in the LR Develop module, you can save the changes you've made as a "Snapshot."  This lets you go back to that version easily after you play more.  I can see that being useful in making "before" and "after" pictures to compare and share.  I used some of the tips that I learned to edit the picture below.

Here's the "before" image that needs some work.

Here's the "after" image.
I think editing is useful in making a good picture better.  I like subtle edits.  This picture needed to be lightened -- it was underexposed and too dark.  After adjusting the exposure, I used the eye dropper to adjust the white balance slightly.  Then I used brushes to whiten her teeth and smooth her skin ever so slightly.  Can you tell? Last of all I used a brush to further increase the exposure on the left side of the picture below her arm. 

Here are two of the sites that I looked around at yesterday: