thanks for your feedback guys (:
I did a quick google search on "alcatraz" and looked under the image tab, and found other similar shots to mine. I do agree that the shot looks rather bland and needs an extra element (i.e. a lone sailboat in the water, some nice cloud formations etc2.). The next time I visit Alcatraz, I'll try something different.
Somehow when i do this using the 'layers' in photoshop, it looks exactly the same as before. How do I go about doing this exactly? Do i selectively increase saturation and adjust the brightness/level of certain parts of the photo?