To keep sand away from your food and belongings during a beach picnic, pack your items in sealable bags or containers and keep them in a closed picnic basket or cooler until you're ready to use them. Additionally, use a fitted sheet as your picnic blanket, placing your cooler or bag at the corners to create raised edges that help to keep sand out. Lastly, consider bringing a small brush to gently sweep away any sand that might find its way onto your items.