Where is the focus point set on your camera for this shot? When I first started using my Canon (just a 1000D) I was bitterly disappointed with the pictures I was getting as the real subject of them was in soft focus whereas other areas were sharp. Then I noticed where the camera was focusing and altered it to be in the centre and everything started to come right. I find the lens you use is good in bright light but a little soft as things get darker but I would expect a shot like this sunset one to be much sharper. If you know someone with another Canon you could try borrowing their lens and see if is that.
One of these days you will say WOW though and that's a day worth working towards.