There are 2 common ways you can adjust White Balance in your camera when you take your image and in Photoshop when you edit your image. I typically set my camera to an auto White Balance. I use the Nikon D700 & the auto White Balance is awesome, but not always perfect. Therefore, I clean up the White Balance in Photoshop. This trick can be performed in both Photoshop Elements & CS.
Step #1 - Open the "Levels" palette. (short cut is command/control L)
Step #2: Click the White Balance Dropper. The white arrow is pointing to the White Balance dropper and the black arrow is pointing to the Black Balance dropper. I typically use the white first and the black second.
Step #3 - Click on the image on the color you would like to set as the White Balance. I clicked on her white tank top. Then do the same with the Black Balance (I don't Black Balance every image, just ones that need it.)
Here are a few more examples..
This is just one of the tricks you'll learn during my Photo By You Workshop. I also offer 1 on 1 Photoshop lessons. I used my Photo By Emilie Color Action for the final edits.