Conventional photography rules state that all parts of your subject should be in sharp focus. However breaking rules is another path to success. Bokeh is the aesthetic out-of-focus part of the image.
Create a deliberately out of focus image like the one below :
by following these steps :
1. During the festival season be on the lookout for objects like Christmas trees draped with lights.
2. A tripod is absolutely necessary to steady the camera during such lengthy exposures.
3. On your lens change the lever from 'Auto-focus (AF)' to 'Manual Focus (MF)'
4. Press the 'Q' button at the back of the camera to bring up the 'Quick Control Screen' on the LCD monitor. Select the 'Drive Mode' setting below the 'ISO' speed setting in the upper right corner. Set the 'Drive Mode' to '2 second self timer'. This will prevent camera shake due to shutter clicking from affecting the picture.
5. Turn the manual focus ring on your lens until all the lights are suitably blurred and then click the picture.