I found great looking cupcake tin liners at IKEA - they reminded me of small pleated lampshades. Within minutes, I created a softer look on a strand of bulbs hanging in my garden.
Using an X-Acto knife, make a cross cut in the bottom of the liner. Remove bulb from socket - slip on liner and replace bulb.
You can find these in the kitchen supply section at IKEA. A package of 65 is $0.99.
If you're using these indoors - the paper liners are fine. However, outdoor use won't stand up to rain - so you'll have to slip them off when you're through.
One package contains three different styles - so you can mix them up or use all the same.
Although I have never had a problem – please use caution and do not leave lights on when not present. Also – make sure paper liners do not directly touch bulb. This project is not meant for long term use.