First, you need some cotton batting, a paper lantern, and three flameless candles, the type that Glade sells. Pull at the cotton batting until it looks fluffy, light, and cloud-like. Then, hot glue it to the outside of the paper lantern in various places. Make sure it's fluffed to your liking, then light the lights and stick them inside. Hang the lantern wherever you'd like.
How To: Make Your Own Surreal DIY Cloud Wedding Backdrop - A Practical Wedding