The first thing to do is to check the lens for fingerprints or dirt.
Turn the camera on and closely examine the glass front of the lens.
If it needs cleaning, use a soft cotton cloth.
If you need moisture, just breathe on the lens and then clean the lens with the cloth.
Not all my pictures with this camera are as sharp as I would like, though the
ones that are sharp are excellent.
What can I tweak (eg white balance, compression)? The softer
pictures can be tweaked and sharpened in Photoshop, but
the pictures I am taking with this camera are not as universally
sharp as with the SD400. I think there was a control for sharpness
level in that camera, but may be wrong.