Most digital cameras today auto focus and auto expose when the shutter button is pushed down slightly just before the picture is snapped. This often leaves you with a photograph that is either too light or too dark. I make a habit of pushing the button down slightly and giving the picture a quick look while still aimed at the subject. If the picture seems too light, I release the button, point the camera into an even brighter area where there is more sun and again push the shutter partway down. Then I swing camera back to where it was originally and the resulting photo will be darker.
Conversely, if the photo seems too dark, swing the camera into an area that is even darker, press the shutter slightly to expose for that darker area and while still holding down the shutter slightly in order to preserve that exposure, swing the camera back into position and your picture you want will be lighter.