I always enjoy photographs of places that I will probably never visit, so thank you!
Overall, these have that familiar "beginner snapshots" kind of feel.
#1 could have been better if you had chosen a subject, whether a certain storefront, a pedestrian, or some other object. Showing something in context is a very powerful photograph that informs the viewer.
#2 could have been either tighter or wider. Tighter to show only the houses and not so much skyline, or wider to include all of the spires (one of which is chopped off here).
#3 I perceive as an attempt to show a juxtaposition between old and new, and it would work better if once again you would have chosen to concentrate the photo on just exactly what about the scene that made you look.
... And these are great advices! Thanks allot, all make sense and are highly appreciated! Prague is my home town for a few years now and I'll keep exposing them. Thanks again, Liviu