Second picture , I don't think you used a tripod? For night photographer / long shutter speed shots , you'll need a tripod for sure. I think you can get some at Wal Mart for very little money just to start with.
Third picture needs a little bit of straightening and if you want it centered , make it centered not someone between to the side and centered.
The rest I guess will come after a while of taking photos. You'll see things in differently , like that whats worth to take and whats not. You'll realize that the angle you take the picture with makes a big different too.