From the Archives at Digital Photography School, 10 important questions to ask yourself when composing a photo.
1) What story am I telling?** Basically you are asking yourself “Why am I taking this shot? What’s is it’s purpose and what am I trying to convey?”

2) What is the visual focal point of this shot? Once you’ve identified the focal point you can think about where to place it in the frame.
3) What competing focal points are there?** You know where you want your viewer’s eyes to be drawn to and have placed it where you want it in the frame. Now, look over the rest of the shot and see if there are any competing focal points and whether they add ot take away from the image.
4) What is in the background and foreground?** Check the background for clutter, and consider if you want the background to be in focus or blurred.

5) Am I close enough? A lot of photos fail because the subject it too small. Often shots where the subject fills the frame are more dynamic.