To keep sandwiches from getting soggy, start by spreading a thin layer of condiments or spreads on the bread rather than piling them on. Use ingredients that have a low moisture content, such as lettuce, cheese, and cured meats. Place wet ingredients, such as tomato or cucumber slices, between dry ingredients to create a barrier. Avoid packing the sandwich too tightly in a plastic container or wrapping too tightly in plastic wrap, as this can trap moisture and cause sogginess. Consider using a crusty bread or toasting the bread slightly before assembling the sandwich.