If it makes you think a little, or feel a little, beyond the usual "what a pretty flower" or "what an awesome HDR", try to figure out why. What is it in the image that makes you feel that way?
Some elements of the visual vocabulary:
- Darker vs. Lighter
- High contrast vs. Low contrast
- Color temperature (this applies to B&W too, as tonining)
- Where is the subject in the frame?
- Point of view (low, high, left, right)
- Angle of view (wide, narrow)
- What is emphasized, and how?
This might seem like art nerd wankery, and it is, but if you can learn to read the language a little, you've got a better chance at speaking it.