Here's the third light rule again.
Backlighting has two effects:
1) Emphasizes the shape of the subject
2) Separates the subject from the background
Backlighting emphasizes the shape of the subject because the subject is darker than the background.
Here, the cattails are so dark, they're silhouetted.
This dark/light contrast also separates the subject from the background.
Backlighting may brighten the edges of the subject, as seen in this detail below.
This edge lighting create separation.
If you're photographing a still life or doing a portrait, consider add light to the subject with fill flash or a reflector.
Fill flash is often too bright, and too blue.
Set the flash exposure compensation from -1.0 to -2.0 to darken the flash.
Try setting the white balance to the flash icon to decrease any blue color caste.
You can also filter the flash with an amber filter.
When photographing toward a bright light source, flare may occur.
Flare can enhance, and can also be a detriment.
If the later, use a lens hood.
Or, block the flare by placing your lens in shadow.
Hold your hand up to block the light.