First find a great gluten-free recipe. I used a recipe for a baked macaroni & "cheese" from the Gluten Free Goddess blog (lots of great recipes there). Find something that suites the recipient. Type up the recipe and print it out on fun paper or a cute recipe card.
Collect a few ingredients from the recipe and assemble them together in a baking dish or something relevant to the recipe (use a cake pan for a cake recipe, a salad bowl for a salad recipe ... you get the idea).
It's actually quite fun to hunt for things. I found this gluten-free mustard in my local health food store. I don't know if regular mustard has gluten in it, but this one sure doesn't! I also added a few other cooking related things (there's some pot holders, a matching dish towel and a pot scrapper in there).