First of all, mainly as a pet peeve more than anything else, but if you are doing photography for art purposes rather than like a family holiday, I've always been inclined to turn the date-stamp at the bottom right off. That said, each to his own. ;)
Ok, you've got some nice photos but the best ones seem just to be the best because of the content, not so much the techniques used. That said, your first and second last photograph are a little boring, only because the content isn't particularly fascinating, and you haven't used any fancy shutter speeds or framing to achieve something a little more interesting. Again, your last image of the glitter on the window is actually quite nice to look at, however if you had framed it a little better (straight on, maybe capture the full window frame as well) it would be a really great photo.
I'm not sure what kind of camera you are using, whether you have more than one lens and stuff like that, but if you take one thing from this comment, take framing. When you see something you want to photograph, don't just take the picture straight away. Look through the viewfinder / screen and see what it looks like. Then move around a little bit, play closer and further away and see what looks better. Just take your time taking the photos is what I'm saying. If you want to see Photography as art, you need to appreciate that art takes time. Just because photography can be done quickly, it doesn't mean it should.
Hope that was alright as general comments and not too harsh.