Hi Hjx, thanks for posting the pics.
Here's my humble feedback. Like one of the poster mentioned earlier, historical places like Prague and Vienna ooze with character. The buildings, ppl on the street, the stone pavements, etc etc etc.
Perhaps you were on a business trip/package tour, and didn't have time to get upclose with your subjects, coz the shots you took say very very little about the character of the place.
For instance, the superb buildings were taken from a far, perhaps you wanted the whole scene to be in frame. Unfortunately, that greatly distances the subject from the viewer, and tells nothing about the subject besides the fact "I was there".
I too was a victim of squeeze-all-you-can-in-a-frame variety, especially on trips I had no control over. What did help though, was to take shots while in transit, like while on a taxi, train, etc., of the fleeting moments around you. That would've told the viewer tons about the great places you were in.
Unlike those great breathtaking shots of buildings, landscapes we see from pro shooters, we mere mortals often don't have the luxury of time to wait around our subject for the desired combination of weather, lighting, etc. So often we're jinxed by the curse of the "boring dull sky". Most of the time, the sky tends to be flat, monotonous, and simply sucks out any single thread of remaining inspiration from the foreground. To counter that, I personally found either tightly framed shots of an interesting part of a building, or a very very close wide angle shot often helps.
Hope to see more pictures from your future trips! Keep on shooting!!