First, welcome to POTN! This is a great place to learn - just don't take things too personally if people get a bit "sharp-tongued" sometimes. I have learned a ton here, so I hope I can pass on some of my learning too...
First, research "The Rule of Thirds". It is a compositional tool/framework that helps to make your photos better and more appealing to most people. I think just a slight change in the location of your main subject in a few of these would make them a lot better - even if you don't have time to really set up the composition the way you want. I like the times you took the pics - they are a great place from which to start!
Secondly, I would recommend a book - "Understanding Exposure" (I believe by Brian Peterson). It has great examples and ideas on how to make sure you expose as well as possible for the situation in which you are shooting. I still refer to that book when I have questiosn.
Finally - I would recommend that you take the time to compose a bit more. I know you said you didn't have time, but I learned that taking a bit more time per photo (and having fewer photos) usually meant I was getting better images. Also, always think compositionally (if that's a word). I try to see my images before I raise the camera to my eye. Just that tiny bit of planning will help you a lot.
I like what you are doing as a start - keep taking pics and keep posting. Also, look through the forum (especially the lens sample archives) for photos and see which ones you like. YOu can try and mimic their style while still keeping your own ideas at the forefront.
Have fun!
