The way I cook an egg is like this. I take the egg, crack it in a bowl, pierce the yolk, then whisk it a bit. Then I add a bit of soy sauce, and fry it in a pan. However, the egg always come out a little bit flat, and hard, so is there a remedy to this?
Yes, a few suggestions:
(1) You are most likely cooking it at too high a temperature. Scrambled eggs will come out maximally tender if you do them over very low heat, stirring almost constantly. High temperatures cause the egg proteins to knot up and become tough. For 4 eggs, figure on at least ten minutes of slow cooking.
(2) You can incorporate more air by whisking more vigorously, or if you want them really fluffy, by running them in a blender before cooking.
(3) To increase tenderness, you can also add an extra egg yolk, or more butter.
Another thing to recognize and beware of is the age of your eggs. Fresher eggs are fluffier than old eggs.
Adding a bit of whole milk will help with the fluffiness. According to Cooks Illustrated, the fat from the milk will actually separate the protein strands in the egg and allow more air into the mixture.
Use a medium heat and a lid (or upside down plate) on the pan so that the eggs are steamed as well as fried. You will find they go extra fluffy!
If you want real scrambled eggs try my technique for that Better Scrambled Eggs
They recommend that you use a hand blender to make the mix frothy. Alternatively, you can use a hand blender on just the whites, then fold into the yolks later.
Adding cold water to the eggs will mixing will also help increase the fluffiness. You can guesstimate 1-2tbsp for 4 eggs.
Obviously whisking the hell out of it definitely helps a lot.
In the book "The Science of Food and Cooking" by Allan G. Cameron, it is mentioned that eggs are acidic, this book also devotes a large section to leavening. My brother, after experimenting a bit came up with the proportion of 1/4 teaspoon of baking powder to every two eggs. This works really well for any type of mixed egg, quiches included. It also seems to work better if the baking soda is added to a small amount of water to dissolve and then mixed into the eggs.