Simply draw a realistic drawing of the DNA, try to add it as much details as possible. You can also use furnitures or recycling items around you if you're making a model, for example...
you could use fuzzballs or marbles for the outside, and perhaps thin construction tubes for the DNA strands?
Maybe twist paper against a pencil for the outside, with a pencil being used as the DNA strands? I sincerely hope this helped!
