Namely: keep it simple. One of the easiest ways to improve your photos is to take stuff out.
You can do that in many ways. Zoom in. Get closer. Rotate. Blur the background. Move things. Change your position. Use obstacles in between. Use light, or rather darkness. Even for simple shots, always think “what can I take away?”.
Like in this snap of one of my bedside lamps, just now:
Just a Fuji X100 snap while testing a setting. But even for a simple snap: what is the alarm sensor at the top doing in the picture? A simple change of viewpoint and rotation gives me this:
Personally, I would crop off the bottom. That joint between the two rods has no place in a picture. Since the x100 is a fixed lens camera, it is best done in post-production here.
Simplifying your pictures is easy, as long as you remember to do it. My rule: everything in a picture has to be in it for a reason – or it shouldn’t be in it. If you start doing this even for snaps, it will become second nature, and your photos will look more “professional”.