Christina,
I'm a bit late to the party but I wanted to say that I really thing that the last image that you posted is a lovely composition and the best of the bunch IMHO. I think that Mike's suggestion about the water is a good one but that you didn't take it quite far enough in your edit. The background bridge did lose some pop as well. Get those two thinks sorted out and then print it and put it on your wall as a sign of your progress
I wonder what made you choose the other compositions over that one when you started the thread? I ask the question to get you thinking about your selection process.
I also wonder why you aren't saving the edits that you post here? It seems to me that it would often be much easier to make changes to an existing edit than to start all over. Trust me, I do it ALL the time...