Start with a good photo. Mess with your camera settings and take as many shots as you can.
Start with the basic changes. Move each setting and see what you think looks best. I slightly increased the clarity here ^
Exposure: I chose to keep it about the same, as with Contrast. But each photo will be different
Saturation: Brighten the colors, I used this to brighten the color in the eye
Color temperature: this is my favorite, it really changed the whole feel of the picture
Darken high lights and lighten shadows: I used this to blend the colors a bit more, it sort of acts as a neutralizer
Denoise: More blending. Just try to keep all the edits low, overediting can ruin a picture.
The colors: Use these to increase or decrease red greens and blue amounts.
Use curves to brighten or darken a full photo
You can also use the presets or change it to B&W. Sometimes this improves photos, but I chose not to on this.
Before and After
Use different cameras and techniques. This was taken with my laptop webcam
This one was taken with my camera
This one was taken with my iPod 4g