Score lemons lengthwise and peel away from the fruit to get two full half peels.
Push a small star-shaped cookie cutter through the peel to create a lemon peel star. You should get 4 stars for each lemon.
Allow the stars to dry.
Use waxed thread or twine with a large needle to thread the stars in equal intervals.
Hang the string of lemons on the mantel, a Christmas tree or anywhere you want.
Notes
If the lemons are too dry and curled when you go to work with them you can soak them in a bit of warm water for a few minutes.I used about 4 dozen stars for my 8 foot mantel. You could measure out how long you want your garland first and get an idea of how many stars you will need.