Archaeological evidence suggests that the first griddles were flat rocks, heated with fire and used for making unleavened flatbreads and other foods. Today's griddles are a little more sophisticated--we have Teflon now--but the overall design remains the same. A griddle is still a smooth, flat surface that allows for even heating and is used primarily for making foods that require a low-to-medium heat such as pancakes, tortillas, crepes and very tasty grilled cheese sandwiches.
Put a little oil on the griddle with a paper towel. You won't need much, as most griddles have a good non-stick surface to them. Rub just enough on the surface to create a slight sheen. You can leave out this step by simply oiling the food you are going to be cooking, such as buttering the bread of a grilled cheese sandwich.
Preheat the griddle. Cooking anything on a cold griddle simply won't work very well. Start off on a medium setting and test the amount of heat by splattering a little water on it. The water should sizzle a little but not pop off the surface. If it does pop, it's too hot and you'll want to turn down the heat.
Pour or place the food to be cooked onto the surface. Because it's a flat surface, you'll want to make sure the griddle is secure and on even footing, or your food, particularly something like scrambled eggs, will start sliding off the edge of the pan
Cook your food like you would in any other frying pan. The griddle should cook everything nice and evenly.
Clean the griddle after it has cooled down by simply wiping it with a cloth or paper towel.