Omelets are great because you can make them as complicated or easy as you like. Also, you can just add whatever you have. The hard part of omelets, of course, is the technique. If you get it wrong you end up with either one ugly omelet or scrambled eggs. Rest assured, both will still taste good.
In my omelets, I like to scramble my eggs in a bowl and add a little milk. I think the milk makes for a fluffier omelet, but that's just me. This is also where I add the mix ins, in this case spinach, olives, and cheese. You would also add your spices now.
Heat up a small non-stick skillet. Try to use one the same size you want your omelet to come out. Coat the bottom with olive oil, this will make it easier to flip and will also add flavor.
Pour a thin layer of your mixture onto the hot skillet. Let it set until it looks like the edges have formed. (Sorry I don't have pictures for this, but it's hard to be camera man and chef with omelets.) Now take your spatula and pull the edges away while tipping the pan so the runny liquid on top runs to that spot. Continue to do this until there is no more runny liquid--the top of the omelet will still be uncooked, but the bottom should be done and the edges formed. Gently loosen the edges and bottom of the omelet. When it is loosened gently flip over and let the top finish cooking. Slide out of pan onto place and fold in half with spatula.