Cooking scrambled eggs over high heat means that your eggs will be done quicker, but it also means that they'll most likely be dry.

To ensure that you end up with moist, fluffy eggs, scramble them over medium low heat, and remove them from the heat just as they're starting to look done. They'll continue to cook even after you remove them from the stove.

Adding a little water can also help to make sure you get the right texture.