Cemetary shot for C&C

[Helter]

Hey Everyone, I shot this one just on (P) but manual focus with Canon DS6041 and 18-55 mm lens. Im a noob but I learned how to change aperture and shutter speed but still don't totally understand when to change. By the way, I took this at a little cemetary by my house that I've always loved. Also, I think the left side should be cropped a little bit but im not home at the moment and don't have PS on laptop.
(Image Resized)

 

[white]

Im a noob but I learned how to change aperture and shutter speed but still don't totally understand when to change.

Think of them as creative controls. When to change them depends on the effect you're after.