I used popsicle sticks that I purchased at the craft store (6" x 3/4"). You can certainly repurpose sticks from the popsicles you have eaten. You can leave them natural color, paint them or buy them already colored. I sprayed mine with a light coating of Heidi Swapp's color shine, Sweet Cherry.
Cut off the top portion of a holiday or greeting card and glue it to the popsicle sticks. I used a liquid glue (Alene's Tacky Glue or Elmers). After the glue dries, using an sharp blade, cut between each of the popsicle sticks.
Then put them back in order!
I bagged my puzzle for safekeeping. This card had a small picture on the back so I cut it out and taped it to the bag.
Enjoy your puzzle and have a safe and Happy New Year!