Starburst effects can add an interesting element to a photograph. In a dark scene, it can add a dreamy, peaceful twinkle to the lights. In a daytime scene, a starburst sun can add drama and interest (Diy Photo Lighting)
A very handy cheat sheet for beginners summarising the relationship between aperture, shutter speed and ISO. It also shows, in a simple manner, the impact of the adjustments made to aperture, shutter speed and ISO.