In terms of what to do, you're already doing it: Grab your camera, head out, experiment, play, and learn.
In terms of what to get next, the examples you posted are all nighttime or low-light photos. If you don't already have one, a tripod would be a good thing to add to your kit. (And a good idea for a drop!)
Down the road, if you want to keep improving as a photographer, you must become a ruthless editor. Each time you go out and come back with photos, ask yourself, "Would I hang this on my wall?" If the answer is yes, try to develop the photo into something you'd print and hang. If not, discard it and move on. Visit exhibits and gallery showings and try to figure out what kind of photography appeals to you. (I'm a landscape guy.) Go back to your own photos and ask yourself, "Would I put this in the gallery next to the photos that spoke to me?" If the answer is no, try to figure out why not. Go back out with new ideas to try.
But never stop playing. That's where the fun stuff happens.