Car decorations may vary, if you want it more attractive even without occasion then you can do any thing to it, but just make sure that it won't look like a mess. For car decorations on weddings, things could be a lot different because you don't need all those stuffs mentioned above. The design should be something flare and modest. It doesn't really colourful lights like led, but doing car decorations for wedding can also be decorated with colors, basically the colors should match with the motif. Let's say if the motif is blue, then you can decorate blue laces in front of the car and at the side of the car window.