The original, non-blurry image is to the left. The blurred version is to the right. Same concept - rather than random blur, we have intentional, controlled blur. The question is, how did I do this?

Step 1: Figure out how to control blur, and replicate the images above
Once you've figured out how to achieve the two images above, you can start getting more creative.

Step 2: Get creative and make controlled-blur shots of your own