You will need:
Battery operated tea light (from eBay)
Double sided tape
coloured light card or scrap booking paper.
Straight cut scissors
Wave cut scissors.
Measure 10cm x 1.5cm of the paper with the straight scissors, then trim one edge with the wave cut scissors. Attach around the lower half of the tea light with double sided tape.
Attach to the roof of your house with double sided tape.
The ones I bought twist on & off. If the tea lights you buy have a different on/off mechanism you might need to adjust this the suit them.
Also you can use ribbon or lace instead of paper, & if you don't have double sided tape you can use glue, but I found that a bit tricker (as you have to be careful not to get glue in the light mechanism or accidentally glue the light together).