How much gluten will set off somebody's celiac disease?
I am celiac. Ideally you should clean your entire kitchen, clean out your silverware and utensil drawers and wash all utensils in the dishwasher. Wipe all surfaces and sinks with bleach wipes. Scrub all pots and pans, to remove gluten films then wash in dishwasher. 
give all dishes to be used a run through the dishwasher. 

Off limit items are seasoned pans (cast iron, or porcelain), earthenware, pasta pots, strainers, toasters, cooking stones, wood spoons or utensils, cutting boards, blenders and crockpots.

To avoid contamination use fresh mayonnaise, mustard, peanut butter jars, etc.
Do not use any ingredients such as sugar that may have been contaminated with flour from use while baking. 

Because you are not familiar with ingredients that contain gluten, use only pure ingredients if you are cooking for your celiac guest. 

Avoid spice blends.

Also see: Unsafe Gluten-Free Food List (Unsafe Ingredients)