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)
Learning even just the basics of photography takes a bit of work and one of the more complex ideas is the relationship between ISO, aperture, and shutter speed. Lifehack has a graphic that helps make sense of it.