Get your pan hot but not smoking.
Whisk at least two eggs with a little milk & some ground pepper, place it the pan and leave for a couple of minutes. If you move it around straight away it will break up and look like scrambled ( that's another recipe)
At this point if the eggs is still runny in the middle, gently lift the side of the omelet whilst tilting the pan slightly so the liquid will go round the side to cook.
When nearly done add cheese or (favourite filling) then flip the empty side over great, it should be nice and brown.
Other fillings: chopped pre-fried bacon pieces, mushrooms, fresh chopped tomato is nice as well.
If you are doing more that one you will always find the second one comes up bigger? I think it's beacause the pan is nice and hot now.
Sorry it's so long. Good luck