Even if there are no current customers, keep items prepared on the grill. The faster you are able serve your customers, the larger their tip. However, make sure you do not overcook the food and end up burning it. Each customer has a bar that starts out in the green and drops over time. The longer that bar decreases, the less money they will pay when served. If you let the bar disappears completely, they will leave. Always give priority to customers who have been waiting the longest.