I have wrote a tutorial how to use Picasa to enhance photo and dedicated to photography newbie.
Posted in our new blog as well http://www.pixelraves.com
Step 1: Double click to open the picture you would like to enhance
Step 2: Now you are in the editing view
Step 3: Click the Tuning tab, adjust Highlights to increase the brightness and adjust the Shadows to increase the contrast of the photo. This photo color too warm, I have adjusted the Color Temperature to left to reduce the warmness.
Step 4: Now click on Effects tab for more enhancement. I have selected Saturation and to give the photo a little bit more vivid.
Step 5: Next, I click Glow to give the photo some gauzy glow feel.