When I got my first camera, I did exactly what you did, and shot anything I could. I looked for stuff everywhere, tried to take shots I thought were "good", and basically ended up with a whole bunch of stuff that might have been technically correct but didn't give me much satisfaction.
Since you're just starting, and this is just my perspective, the best advice I could give would be to shoot things you enjoy and have a good time. You'll get better with practice, after handling the camera for a while, and learning how it works. You have some interesting shots, but I kind of get the feeling that, like you said, these were just images of "things that you found' rather than things you were invested in.
I tend to gravitate more towards the "creative" side of photography rather than the "technical", and I'm sure you'll get some solid advice from others on here with regard to the ins-and-outs of photography, and what you need to do to make your images more technically correct. But I think those things usually fall into place when you're having a good time and you really care about what you're shooting.
Keep up the good work... you're off to a great start.