These should help you. Best of luck with it.

When I was younger I made a model for a double helix strand of DNA. To make this you would take a small piece of wood and use 2 pieces of metal coat hanger. Twist the ends of the coat hanger to form the double helix and stick the bottom ends into the wood to hold them up. You can then add some glue at the base to make sure that the wire doesn’t come out. Get some very fine wire which you should be able to pick up in the craft section of walmart and then use that to string from one side to the other to form your chains in the helix. On this wire you’ll want to also pick up some beads (blue, green, yellow and pink or orange) and you can also get these at walmart in the craft section. You’ll put two different colors on each strand to show how they pair with each other. Green = Adenine, Blue = Guanine, Yellow = Thymine, and Pink or even Orange = Cytosine. Adenine pairs with Thymine and Guanine pairs with Cytosine. You’ll also want to write this color chart on a small piece of paper and glue it to the wooden base so that anyone who views it can see what you did. I’ve also see this done with legos. You can view photos of this by going to yahoo images and searching DNA or double helix. Here are some photos http://i12.photobucket.com/albums/a244/erika78750/DNA2.jpg

http://i12.photobucket.com/albums/a244/erika78750/DNA.jpg