Choosing the focus in your image

I was having coffee with a friend today and I took these photos to demonstrate to her how to make something close up (the coffee cup) in focus without making it the center of the photo. Very simply put, you can put the camera in front of the cup and push the button down half way to "hold" the focus. Then while the button is still held halfway down slide the camera to the position you want for your picture and push the button the rest of the way down. This way your picture looks like the one above instead of the one below (where the camera would naturally focus on the center of the shot when you push the button all at once).