Hanging lights on branches. Go natural with a fat branch and hang a combination of ornaments and candles attached with wire. Use twine or strong fishing wire to suspend the branch from above. You might want to try hangers so as not to damage your ceiling.
DIY: How to make a cloud! Wish I had know this when Nadja asked for a cloud for Xmas, we only came up with a dry ice version. She still has a jar of "condensed" cloud though. The cloud can be suspended from ceiling with light behind