Welcome to the forum and thanks for posting these.
My first impressions (not studying the pictures or very long) are:
#1 - Nice idea but the crop is perhaps a little bit too tight and I find the big black space on the left distracting.
#2 - I would see the main focal point as being the 'note' which to my eyes is out of focus and slightly over exposed. It would be great if you could make that 'pop'.
#3 - Has far too much going on. The buildings are covered by the trees and the fountain competes with the trees and the spray competing with the blossom. I don't like the half chopped building on the left.
#4 - Interesting picture but perhaps two pictures in one. Also the bridge cuts the picture in two (read up on the 'rule of thirds').
#5 - Great picture; I really like it and in my opinion the best.
I think the pictures are a great first attempt and different people will have different opinions. These are just my immediate impressions of how you could improve them next time.