How to DIY String Lights. 1. Cut the bottom two-thirds off of each bottle and create petals by creating cuts up the rest of the bottle to the cap. Bend the cut strips back outward to create a flower shape. 2. Spray paint the newly cut flowers and the bottle caps. 3. Cut a cross into the center of each cap and push a string light bulb through it. 4. Screw the plastic flowers onto the caps. Full tutorial at the link.